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ROLLOUT 2 · Pyomo/pyomo

pyomo__pyomo-3017

Solved
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System instructions 4,822 characters
You are a principal Python software engineer resolving a repository issue in `/workspace`.
Your sole objective is to produce a minimal, root-cause source patch that passes every hidden fail-to-pass and pass-to-pass regression test on the first grading run.

## Critical Environment & Grader Rules
1. **Air-Gapped Sandbox & Available CLI Tools**: No network access. Never run `pip`, `uv`, `conda`, or `git fetch`. Note: `rg` (`ripgrep`) is NOT installed in the container — always use `grep -rn --include="*.py"` for fast exact searches so you never waste a tool call on `command not found`.
2. **Protected Grading Paths**: Before running official verification, the grading harness **strips and reverts all changes** to `tests/`, `test/`, `testing/`, `test_*.py`, `*_test.py`, `conftest.py`, `pyproject.toml`, `setup.cfg`, `pytest.ini`, and `tox.ini`. Every part of your fix MUST reside in non-test production source files.
3. **Untracked File Trap (`git add -N .`)**: `submit_patch` stages ALL untracked files inside `/workspace`! Never leave reproduction or scratch files inside `/workspace` — run reproductions inline via `python3 - <<'PY'` or inside `/tmp/repro.py` in a single `run_command`.
4. **Stdout Truncation Rule**: `run_command` truncates stdout after the first 5,000 characters from the TOP. Always run pytest quietly with short tracebacks:
   `pytest path/to/test_file.py -k pattern -q --tb=short --no-header`
   If a test file is large, redirect output to `/tmp/pytest.log` and inspect `tail -n 80 /tmp/pytest.log` so failure tracebacks at the bottom are never cut off.
5. **Strict Pacing Discipline**: `get_status` and `submit_patch` are free and do NOT count toward `max_tool_calls`. Target **16-22 counted tool calls total**, and **begin your first `edit_file` change no later than tool call 15**. Reserve at least 4 calls for verification, `git status --short && git diff`, and submission.

## Execution Protocol

### Phase 1 — Pinpoint Code & Tests Immediately (1-2 tool calls)
- The user message already contains `Workspace Layout` — do NOT waste a turn running `ls` on top-level directories.
- Run a single compound `run_command` with `grep -rn --include="*.py"` to locate:
  (a) the exact symbols, error strings, or functions from the problem description,
  (b) **all parallel or sibling implementations** (for example sync + async variants, `Client` + `AsyncClient`, serializer + deserializer, multiple backends/dialects, base + subclass methods, `__init__.py` / `__all__` exports), and
  (c) the closest existing unit test files under `tests/`.

### Phase 2 — Deep Read & Spec Anchor (2-5 tool calls)
- Use `read_file` with generous `start_line` and `end_line` windows (180-300 lines per call so you read whole modules in fewer calls) on the target function/class, callers, type annotations, and neighboring tests.
- Before editing, verify every explicit and implicit requirement from the issue: exact parameter names, defaults, boundary/domain edge cases, exception types/messages, `None` vs empty collection vs falsy (`0`, `False`, `""`) semantics, mutability/copying, and return types.

### Phase 3 — Reproduce Bug in One Call (1 tool call)
- Run ONE concise command (`python3 - <<'PY' ... PY` or targeted `pytest ... -q --tb=short --no-header`) via `run_command` to observe the exact pre-fix failure. Do NOT spend multiple tool calls writing separate reproduction scripts.

### Phase 4 — Surgical Implementation Across All Parallel Paths (1-4 tool calls)
- Begin editing by tool call 15! Use `edit_file` with 4-6 lines of exact surrounding context copied from `read_file`.
- Update ALL parallel codepaths (sync/async, multiple classes/dialects, type hints) consistently so partial fixes do not fail sibling tests.
- **2-Strike Edit Rule**: If `edit_file` fails twice on the same block due to whitespace or escaping, do not retry `edit_file` a third time — apply an atomic Python transformation via `run_command` and immediately verify `python3 -m py_compile path/to/file.py`.

### Phase 5 — Edge-Case Verification, Diff Hygiene & Clean Exit (2-4 tool calls)
- Run a single compound `run_command` testing both your reproduction + boundary edge cases (`None`, empty input, leading/trailing delimiters, subdomain/prefix boundaries, subclass/async parity) AND the relevant existing `pytest` module(s) with `-q --tb=short --no-header`.
- Run `git status --short && git diff` via `run_command`. Confirm:
  - ZERO untracked (`??`) files in `/workspace` (`rm -f` any untracked workspace files immediately),
  - ZERO modifications to `tests/` or protected config files (`git checkout -- tests/` if touched),
  - Minimal, clean diff with valid imports and indentation.
- Call `submit_patch` once verification passes, then respond with a brief 2-sentence plain-text summary and make NO further tool calls.
Task prompt 8,703 characters
You are evaluating a software engineering task for repository Pyomo/pyomo.

Problem Statement:
Pyomo AD fails with constant Expressions
## Summary

Pyomo AD raises an error when encountering `Expressions` with a constant value.

### Steps to reproduce the issue

```console
import pyomo.environ as pyo
from pyomo.core.expr.calculus.derivatives import Modes, differentiate

m = pyo.ConcreteModel()

m.x = pyo.Var(units=pyo.units.mol, initialize=0)

@m.Expression()
def y(blk):
    return 2

@m.Expression()
def product(blk):
    return blk.x * blk.y

diff_expr = differentiate(
                expr=m.product,
                wrt=m.x,
                mode=Modes.reverse_symbolic
            )
diff_expr.pprint()
```

### Error Message

```console
Exception has occurred: KeyError
"Component with id '1907001786672': 2.0"
  File "C:\Users\[REDACTED]\Repos\pyomo\pyomo\common\collections\component_map.py", line 71, in __getitem__
    return self._dict[id(obj)][1]
KeyError: 1907001786672

During handling of the above exception, another exception occurred:

  File "C:\Users\[REDACTED]\Repos\pyomo\pyomo\common\collections\component_map.py", line 73, in __getitem__
    raise KeyError("Component with id '%s': %s" % (id(obj), str(obj)))
  File "C:\Users\[REDACTED]\Repos\pyomo\pyomo\core\expr\calculus\diff_with_pyomo.py", line 331, in _diff_GeneralExpression
    der_dict[node.expr] += der_dict[node]
  File "C:\Users\[REDACTED]\Repos\pyomo\pyomo\core\expr\calculus\diff_with_pyomo.py", line 442, in _reverse_diff_helper
    _diff_GeneralExpression(e, val_dict, der_dict)
  File "C:\Users\[REDACTED]\Repos\pyomo\pyomo\core\expr\calculus\diff_with_pyomo.py", line 484, in reverse_sd
    return _reverse_diff_helper(expr, False)
  File "C:\Users\[REDACTED]\Repos\pyomo\pyomo\core\expr\calculus\derivatives.py", line 96, in differentiate
    res = reverse_sd(expr=expr)
  File "C:\Users\[REDACTED]\Desktop\diff_expr.py", line 16, in <module>
    diff_expr = differentiate(
KeyError: "Component with id '1907001786672': 2.0"
```

### Information on your system
Pyomo version: 6.6.2
Python version: 3.10.10 | packaged by Anaconda, Inc. | (main, Mar 21 2023, 18:39:17) [MSC v.1916 64 bit (AMD64)]
Operating system: Windows 10
How Pyomo was installed (PyPI, conda, source): From sources
Solver (if applicable): n/a


## Task Budget (Session terminates when any budget is exhausted)
- Time allowance: 7.5 minutes
- Tool calls allowance: 30 calls
- Max loop iterations: 40 turns

## Execution Environment Rules
- Single command timeout: 90 seconds (commands exceeding this fail without ending the session)
- Command output limit: 5000 characters
- File view limit: 150 lines per read_file call
- File character limit: 10000 characters per read_file call
- Environment is offline (no network/PyPI access). All repository and test dependencies are ALREADY pre-installed. Do NOT attempt to run pip install or download packages.

## Instructions:
0. All source code is under `/workspace`. Do NOT search outside `/workspace` (e.g. `/usr/`, `/wheels/`, system site-packages). If imports fail, the issue is in the source code under `/workspace`, not in missing system packages.
1. Analyze the problem statement and any provided hints carefully to identify all requested script paths, CLI subcommands, or Python modules.
2. Inspect existing codebase conventions and test files before making edits.
3. Verify your implementation using targeted tests or inline assertions before submitting.
4. Call submit_patch only after your implementation is complete and verified.
5. As your final action, you must return a text-only response reporting your completion to terminate the session.
## Workspace Layout
The repository is located at `/workspace`. Here is the directory tree (up to 3 levels):
```
./CHANGELOG.md
./CITATION.cff
./CONTRIBUTING.md
./LICENSE.md
./MANIFEST.in
./README.md
./RELEASE.md
./conftest.py
./doc
./doc/OnlineDocs
./doc/OnlineDocs/Makefile
./doc/OnlineDocs/README.md
./doc/OnlineDocs/_static
./doc/OnlineDocs/advanced_topics
./doc/OnlineDocs/bibliography.rst
./doc/OnlineDocs/citing_pyomo.rst
./doc/OnlineDocs/conf.py
./doc/OnlineDocs/contributed_packages
./doc/OnlineDocs/contribution_guide.rst
./doc/OnlineDocs/developer_reference
./doc/OnlineDocs/docutils.conf
./doc/OnlineDocs/errors.rst
./doc/OnlineDocs/index.rst
./doc/OnlineDocs/installation.rst
./doc/OnlineDocs/library_reference
./doc/OnlineDocs/make.bat
./doc/OnlineDocs/model_debugging
./doc/OnlineDocs/model_transformations
./doc/OnlineDocs/modeling_extensions
./doc/OnlineDocs/pyomo_modeling_components
./doc/OnlineDocs/pyomo_overview
./doc/OnlineDocs/related_packages.rst
./doc/OnlineDocs/solving_pyomo_models.rst
./doc/OnlineDocs/tests
./doc/OnlineDocs/tutorial_examples.rst
./doc/OnlineDocs/working_abstractmodels
./doc/OnlineDocs/working_models.rst
./doc/logos
./doc/logos/coopr
./doc/logos/dae
./doc/logos/doe
./doc/logos/gdp
./doc/logos/pyomo
./doc/logos/pysp
./examples
./pyomo
./pyomo/__init__.py
./pyomo/common
./pyomo/common/README.md
./pyomo/common/__init__.py
./pyomo/common/_command.py
./pyomo/common/_common.py
./pyomo/common/autoslots.py
./pyomo/common/backports.py
./pyomo/common/cmake_builder.py
./pyomo/common/collections
./pyomo/common/config.py
./pyomo/common/dependencies.py
./pyomo/common/deprecation.py
./pyomo/common/download.py
./pyomo/common/env.py
./pyomo/common/envvar.py
./pyomo/common/errors.py
./pyomo/common/extensions.py
./pyomo/common/factory.py
./pyomo/common/fileutils.py
./pyomo/common/formatting.py
./pyomo/common/gc_manager.py
./pyomo/common/getGSL.py
./pyomo/common/gsl.py
./pyomo/common/log.py
./pyomo/common/modeling.py
./pyomo/common/multithread.py
./pyomo/common/numeric_types.py
./pyomo/common/plugin.py
./pyomo/common/plugin_base.py
./pyomo/common/plugins.py
./pyomo/common/pyomo_typing.py
./pyomo/common/shutdown.py
./pyomo/common/sorting.py
./pyomo/common/tee.py
./pyomo/common/tempfiles.py
./pyomo/common/tests
./pyomo/common/timing.py
./pyomo/common/unittest.py
./pyomo/contrib
./pyomo/contrib/README.txt
./pyomo/contrib/__init__.py
./pyomo/contrib/ampl_function_demo
./pyomo/contrib/appsi
./pyomo/contrib/benders
./pyomo/contrib/community_detection
./pyomo/contrib/cp
./pyomo/contrib/doe
./pyomo/contrib/example
./pyomo/contrib/fbbt
./pyomo/contrib/fme
./pyomo/contrib/gdp_bounds
./pyomo/contrib/gdpopt
./pyomo/contrib/gjh
./pyomo/contrib/iis
./pyomo/contrib/incidence_analysis
./pyomo/contrib/interior_point
./pyomo/contrib/mcpp
./pyomo/contrib/mindtpy
./pyomo/contrib/mpc
./pyomo/contrib/multistart
./pyomo/contrib/parmest
./pyomo/contrib/piecewise
./pyomo/contrib/preprocessing
./pyomo/contrib/pynumero
./pyomo/contrib/pyros
./pyomo/contrib/satsolver
./pyomo/contrib/sensitivity_toolbox
./pyomo/contrib/simplemodel
./pyomo/contrib/trustregion
./pyomo/contrib/viewer
./pyomo/core
./pyomo/core/__init__.py
./pyomo/core/base
./pyomo/core/beta
./pyomo/core/expr
./pyomo/core/kernel
./pyomo/core/plugins
./pyomo/core/pyomoobject.py
./pyomo/core/staleflag.py
./pyomo/core/tests
./pyomo/core/util.py
./pyomo/dae
./pyomo/dae/__init__.py
./pyomo/dae/contset.py
./pyomo/dae/diffvar.py
./pyomo/dae/flatten.py
./pyomo/dae/initialization.py
./pyomo/dae/integral.py
./pyomo/dae/misc.py
./pyomo/dae/plugins
./pyomo/dae/set_utils.py
./pyomo/dae/simulator.py
./pyomo/dae/tests
./pyomo/dae/utilities.py
./pyomo/dataportal
./pyomo/dataportal/DataPortal.py
./pyomo/dataportal/TableData.py
./pyomo/dataportal/__init__.py
./pyomo/dataportal/factory.py
./pyomo/dataportal/parse_datacmds.py
./pyomo/dataportal/plugins
./pyomo/dataportal/process_data.py
./pyomo/dataportal/tester
./pyomo/dataportal/tests
./pyomo/duality
./pyomo/duality/__init__.py
./pyomo/duality/collect.py
./pyomo/duality/lagrangian_dual.py
./pyomo/duality/plugins.py
./pyomo/duality/tests
./pyomo/environ
./pyomo/environ/__init__.py
./pyomo/environ/tests
./pyomo/gdp
./pyomo/gdp/__init__.py
./pyomo/gdp/basic_step.py
./pyomo/gdp/disjunct.py
./pyomo/gdp/plugins
./pyomo/gdp/tests
./pyomo/gdp/transformed_disjunct.py
./pyomo/gdp/util.py
./pyomo/kernel
./pyomo/kernel/__init__.py
./pyomo/kernel/util.py
./pyomo/mpec
./pyomo/mpec/__init__.py
./pyomo/mpec/complementarity.py
./pyomo/mpec/plugins
./pyomo/mpec/tests
./pyomo/neos
./pyomo/neos/__init__.py
./pyomo/neos/kestrel.py
./pyomo/neos/plugins
./pyomo/neos/tests
./pyomo/network
./pyomo/network/__init__.py
./pyomo/network/arc.py
./pyomo/network/decomposition.py
./pyomo/network/foqus_graph.py
./pyomo/network/plugins
./pyomo/opt
./pyomo/pysp
./pyomo/repn
./pyomo/scripting
./pyomo/solvers
./pyomo/util
./pyomo/version
./scripts
./scripts/get_pyomo.py
./scripts/get_pyomo_extras.py
./scripts/performance
./setup.cfg
./setup.py
```
Turn 1at 51 s601 tokens out5,133 prompt tokens
The user is reporting a `KeyError` when using Pyomo's automatic differentiation (`differentiate`) with a constant `Expression`.

The provided reproduction code is:
```python
import pyomo.environ as pyo
from pyomo.core.expr.calculus.derivatives import Modes, differentiate

m = pyo.ConcreteModel()

m.x = pyo.Var(units=pyo.units.mol, initialize=0)

@m.Expression()
def y(blk):
    return 2

@m.Expression()
def product(blk):
    return blk.x * blk.y

diff_expr = differentiate(
                expr=m.product,
                wrt=m.x,
                mode=Modes.reverse_symbolic
            )
diff_expr.pprint()
```

The error is:
`KeyError: "Component with id '1907001786672': 2.0"`
coming from `pyomo/common/collections/component_map.py`, line 71, called by `pyomo/core/expr/calculus/diff_with_pyomo.py`, line 331, in `_diff_GeneralExpression`.

Looking at the trace:
`pyomo/core/expr/calculus/diff_with_pyomo.py`, line 331: `der_dict[node.expr] += der_dict[node]`

It seems like the `der_dict` is trying to access a key that doesn't exist. `node.expr` might be a constant value (like 2.0) and the `der_dict` is implemented using a `ComponentMap` or something similar that expects components (objects with IDs), not raw numbers.

Let's start by reproducing the issue.
TOOL CALL · run_command
{
  "command": "python3 - <<'PY'\nimport pyomo.environ as pyo\nfrom pyomo.core.expr.calculus.derivatives import Modes, differentiate\n\nm = pyo.ConcreteModel()\n\nm.x = pyo.Var(units=pyo.units.mol, initialize=0)\n\n@m.Expression()\ndef y(blk):\n    return 2\n\n@m.Expression()\ndef product(blk):\n    return blk.x * blk.y\n\ntry:\n    diff_expr = differentiate(\n                    expr=m.product,\n                    wrt=m.x,\n                    mode=Modes.reverse_symbolic\n                )\n    diff_expr.pprint()\nexcept Exception as e:\n    import traceback\n    traceback.print_exc()\nPY\n"
}
Result of run_command 1,199 characters
{
  "status": "error",
  "error_type": "CommandError",
  "error_message": "Traceback (most recent call last):\n  File \"<stdin>\", line 6, in <module>\n  File \"/workspace/pyomo/core/base/units_container.py\", line 1532, in __getattribute__\n    return getattr(pint_module, attr)\n  File \"/workspace/pyomo/common/dependencies.py\", line 75, in __getattr__\n    raise DeferredImportError(self._moduleunavailable_message())\npyomo.common.errors.DeferredImportError: The \"pint\" package failed to import. This package is necessary to use Pyomo units. (import raised ModuleNotFoundError: No module named 'pint')\n",
  "details": {
    "stdout": "",
    "stderr": "Traceback (most recent call last):\n  File \"<stdin>\", line 6, in <module>\n  File \"/workspace/pyomo/core/base/units_container.py\", line 1532, in __getattribute__\n    return getattr(pint_module, attr)\n  File \"/workspace/pyomo/common/dependencies.py\", line 75, in __getattr__\n    raise DeferredImportError(self._moduleunavailable_message())\npyomo.common.errors.DeferredImportError: The \"pint\" package failed to import. This package is necessary to use Pyomo units. (import raised ModuleNotFoundError: No module named 'pint')\n",
    "exit_code": 1
  }
}
Generated tokens 601 tokens · stopped: STOP
<|channel>thought The user is reporting a `KeyError` when using Pyomo's automatic differentiation (`differentiate`) with a constant `Expression`. The provided reproduction code is: ```python import pyomo.environ as pyo from pyomo.core.expr.calculus.derivatives import Modes, differentiate m = pyo.ConcreteModel() m.x = pyo.Var(units=pyo.units.mol, initialize=0) @m.Expression() def y(blk): return 2 @m.Expression() def product(blk): return blk.x * blk.y diff_expr = differentiate( expr=m.product, wrt=m.x, mode=Modes.reverse_symbolic ) diff_expr.pprint() ``` The error is: `KeyError: "Component with id '1907001786672': 2.0"` coming from `pyomo/common/collections/component_map.py`, line 71, called by `pyomo/core/expr/calculus/diff_with_pyomo.py`, line 331, in `_diff_GeneralExpression`. Looking at the trace: `pyomo/core/expr/calculus/diff_with_pyomo.py`, line 331: `der_dict[node.expr] += der_dict[node]` It seems like the `der_dict` is trying to access a key that doesn't exist. `node.expr` might be a constant value (like 2.0) and the `der_dict` is implemented using a `ComponentMap` or something similar that expects components (objects with IDs), not raw numbers. Let's start by reproducing the issue.<channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY' import pyomo.environ as pyo from pyomo.core.expr.calculus.derivatives import Modes, differentiate m = pyo.ConcreteModel() m.x = pyo.Var(units=pyo.units.mol, initialize=0) @m.Expression() def y(blk): return 2 @m.Expression() def product(blk): return blk.x * blk.y try: diff_expr = differentiate( expr=m.product, wrt=m.x, mode=Modes.reverse_symbolic ) diff_expr.pprint() except Exception as e: import traceback traceback.print_exc() PY <|"|>}<tool_call|><|tool_response>
Turn 2at 62 s230 tokens out6,098 prompt tokens
The reproduction code fails because `pint` is not installed, and the code uses `units=pyo.units.mol`. I should remove the units to simplify the reproduction and avoid dependencies that might not be present.
TOOL CALL · run_command
{
  "command": "python3 - <<'PY'\nimport pyomo.environ as pyo\nfrom pyomo.core.expr.calculus.derivatives import Modes, differentiate\n\nm = pyo.ConcreteModel()\n\nm.x = pyo.Var(initialize=0)\n\n@m.Expression()\ndef y(blk):\n    return 2\n\n@m.Expression()\ndef product(blk):\n    return blk.x * blk.y\n\ntry:\n    diff_expr = differentiate(\n                expr=m.product,\n                wrt=m.x,\n                mode=Modes.reverse_symbolic\n            )\n    diff_expr.pprint()\nexcept Exception as e:\n    import traceback\n    traceback.print_exc()\nPY\n"
}
Result of run_command 1,182 characters
{
  "status": "ok",
  "stdout": "",
  "stderr": "Traceback (most recent call last):\n  File \"/workspace/pyomo/common/collections/component_map.py\", line 71, in __getitem__\n    return self._dict[id(obj)][1]\nKeyError: 124199531520656\n\nDuring handling of the above exception, another exception occurred:\n\nTraceback (most recent call last):\n  File \"<stdin>\", line 17, in <module>\n  File \"/workspace/pyomo/core/expr/calculus/derivatives.py\", line 96, in differentiate\n    res = reverse_sd(expr=expr)\n  File \"/workspace/pyomo/core/expr/calculus/diff_with_pyomo.py\", line 484, in reverse_sd\n    return _reverse_diff_helper(expr, False)\n  File \"/workspace/pyomo/core/expr/calculus/diff_with_pyomo.py\", line 442, in _reverse_diff_helper\n    _diff_GeneralExpression(e, val_dict, der_dict)\n  File \"/workspace/pyomo/core/expr/calculus/diff_with_pyomo.py\", line 331, in _diff_GeneralExpression\n    der_dict[node.expr] += der_dict[node]\n  File \"/workspace/pyomo/common/collections/component_map.py\", line 73, in __getitem__\n    raise KeyError(\"Component with id '%s': %s\" % (id(obj), str(obj)))\nKeyError: \"Component with id '124199531520656': 2.0\"\n",
  "exit_code": 0
}
Generated tokens 230 tokens · stopped: STOP
The reproduction code fails because `pint` is not installed, and the code uses `units=pyo.units.mol`. I should remove the units to simplify the reproduction and avoid dependencies that might not be present. <channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY' import pyomo.environ as pyo from pyomo.core.expr.calculus.derivatives import Modes, differentiate m = pyo.ConcreteModel() m.x = pyo.Var(initialize=0) @m.Expression() def y(blk): return 2 @m.Expression() def product(blk): return blk.x * blk.y try: diff_expr = differentiate( expr=m.product, wrt=m.x, mode=Modes.reverse_symbolic ) diff_expr.pprint() except Exception as e: import traceback traceback.print_exc() PY <|"|>}<tool_call|><|tool_response>
Turn 3at 77 s243 tokens out6,774 prompt tokens
The reproduction is successful. The error is indeed `KeyError: "Component with id '...': 2.0"`.

Now let's examine the code. The traceback points to:
`pyomo/core/expr/calculus/diff_with_pyomo.py`, line 331, in `_diff_GeneralExpression`:
`der_dict[node.expr] += der_dict[node]`

And `pyomo/common/collections/component_map.py` seems to be where `der_dict` is implemented (or at least used).

Let's read `pyomo/core/expr/calculus/diff_with_pyomo.py` around line 331 and `pyomo/common/collections/component_map.py`.

First, `pyomo/core/expr/calculus/diff_with_pyomo.py`.
TOOL CALL · read_file
{
  "end_line": 350,
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "start_line": 300
}
Result of read_file 1,526 characters
{
  "status": "ok",
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "content": "_unary_map['sqrt'] = _diff_sqrt\n_unary_map['abs'] = _diff_abs\n\n\ndef _diff_UnaryFunctionExpression(node, val_dict, der_dict):\n    \"\"\"\n\n    Parameters\n    ----------\n    node: pyomo.core.expr.numeric_expr.UnaryFunctionExpression\n    val_dict: ComponentMap\n    der_dict: ComponentMap\n    \"\"\"\n    if node.getname() in _unary_map:\n        _unary_map[node.getname()](node, val_dict, der_dict)\n    else:\n        raise DifferentiationException(\n            'Unsupported expression type for differentiation: {0}'.format(type(node))\n        )\n\n\ndef _diff_GeneralExpression(node, val_dict, der_dict):\n    \"\"\"\n    Reverse automatic differentiation for named expressions.\n\n    Parameters\n    ----------\n    node: The named expression\n    val_dict: ComponentMap\n    der_dict: ComponentMap\n    \"\"\"\n    der_dict[node.expr] += der_dict[node]\n\n\ndef _diff_ExternalFunctionExpression(node, val_dict, der_dict):\n    \"\"\"\n\n    Parameters\n    ----------\n    node: pyomo.core.expr.numeric_expr.ExternalFunctionExpression\n    val_dict: ComponentMap\n    der_dict: ComponentMap\n    \"\"\"\n    der = der_dict[node]\n    vals = tuple(val_dict[i] for i in node.args)\n    derivs = node._fcn.evaluate_fgh(vals, fgh=1)[1]\n    for ndx, arg in enumerate(node.args):\n        der_dict[arg] += der * derivs[ndx]\n\n\n_diff_map = dict()",
  "start_line": 300,
  "end_line": 350,
  "total_lines": 484,
  "is_truncated": false
}
Generated tokens 243 tokens · stopped: STOP
The reproduction is successful. The error is indeed `KeyError: "Component with id '...': 2.0"`. Now let's examine the code. The traceback points to: `pyomo/core/expr/calculus/diff_with_pyomo.py`, line 331, in `_diff_GeneralExpression`: `der_dict[node.expr] += der_dict[node]` And `pyomo/common/collections/component_map.py` seems to be where `der_dict` is implemented (or at least used). Let's read `pyomo/core/expr/calculus/diff_with_pyomo.py` around line 331 and `pyomo/common/collections/component_map.py`. First, `pyomo/core/expr/calculus/diff_with_pyomo.py`.<channel|><|tool_call>call:read_file{end_line:350,filepath:<|"|>pyomo/core/expr/calculus/diff_with_pyomo.py<|"|>,start_line:300}<tool_call|><|tool_response>
Turn 4at 90 s207 tokens out7,544 prompt tokens
In `_diff_GeneralExpression`:
```python
def _diff_GeneralExpression(node, val_dict, der_dict):
    """
    Reverse automatic differentiation for named expressions.

    Parameters
    ----------
    node: The named expression
    val_dict: ComponentMap
    der_dict: ComponentMap
    """
    der_dict[node.expr] += der_dict[node]
```
The `node` here is a named expression (e.g., `m.y` which is an `Expression` object). `node.expr` is the expression it represents. In the reproduction case, `m.y` returns `2`. So `node.expr` is `2`.

`der_dict` is a `ComponentMap`. Let's see how `ComponentMap` is implemented.
TOOL CALL · read_file
{
  "filepath": "pyomo/common/collections/component_map.py"
}
Result of read_file 4,863 characters
{
  "status": "ok",
  "filepath": "pyomo/common/collections/component_map.py",
  "content": "#  ___________________________________________________________________________\n#\n#  Pyomo: Python Optimization Modeling Objects\n#  Copyright (c) 2008-2022\n#  National Technology and Engineering Solutions of Sandia, LLC\n#  Under the terms of Contract DE-NA0003525 with National Technology and\n#  Engineering Solutions of Sandia, LLC, the U.S. Government retains certain\n#  rights in this software.\n#  This software is distributed under the 3-clause BSD License.\n#  ___________________________________________________________________________\n\nfrom collections.abc import MutableMapping as collections_MutableMapping\nfrom collections.abc import Mapping as collections_Mapping\nfrom pyomo.common.autoslots import AutoSlots\n\n\ndef _rebuild_ids(encode, val):\n    if encode:\n        return val\n    else:\n        # object id() may have changed after unpickling,\n        # so we rebuild the dictionary keys\n        return {id(obj): (obj, v) for obj, v in val.values()}\n\n\nclass ComponentMap(AutoSlots.Mixin, collections_MutableMapping):\n    \"\"\"\n    This class is a replacement for dict that allows Pyomo\n    modeling components to be used as entry keys. The\n    underlying mapping is based on the Python id() of the\n    object, which gets around the problem of hashing\n    subclasses of NumericValue. This class is meant for\n    creating mappings from Pyomo components to values. The\n    use of non-Pyomo components as entry keys should be\n    avoided.\n\n    A reference to the object is kept around as long as it\n    has a corresponding entry in the container, so there is\n    no need to worry about id() clashes.\n\n    We also override __setstate__ so that we can rebuild the\n    container based on possibly updated object ids after\n    a deepcopy or pickle.\n\n    *** An instance of this class should never be\n    deepcopied/pickled unless it is done so along with the\n    components for which it contains map entries (e.g., as\n    part of a block). ***\n    \"\"\"\n\n    __slots__ = (\"_dict\",)\n    __autoslot_mappers__ = {'_dict': _rebuild_ids}\n\n    def __init__(self, *args, **kwds):\n        # maps id(obj) -> (obj,val)\n        self._dict = {}\n        # handle the dict-style initialization scenarios\n        self.update(*args, **kwds)\n\n    def __str__(self):\n        \"\"\"String representation of the mapping.\"\"\"\n        tmp = {str(c) + \" (id=\" + str(id(c)) + \")\": v for c, v in self.items()}\n        return \"ComponentMap(\" + str(tmp) + \")\"\n\n    #\n    # Implement MutableMapping abstract methods\n    #\n\n    def __getitem__(self, obj):\n        try:\n            return self._dict[id(obj)][1]\n        except KeyError:\n            raise KeyError(\"Component with id '%s': %s\" % (id(obj), str(obj)))\n\n    def __setitem__(self, obj, val):\n        self._dict[id(obj)] = (obj, val)\n\n    def __delitem__(self, obj):\n        try:\n            del self._dict[id(obj)]\n        except KeyError:\n            raise KeyError(\"Component with id '%s': %s\" % (id(obj), str(obj)))\n\n    def __iter__(self):\n        return (obj for obj, val in self._dict.values())\n\n    def __len__(self):\n        return self._dict.__len__()\n\n    #\n    # Overload MutableMapping default implementations\n    #\n\n    # We want to avoid generating Pyomo expressions due to\n    # comparison of values, so we convert both objects to a\n    # plain dictionary mapping key->(type(val), id(val)) and\n    # compare that instead.\n    def __eq__(self, other):\n        if not isinstance(other, collections_Mapping):\n            return False\n        return {(type(key), id(key)): val for key, val in self.items()} == {\n            (type(key), id(key)): val for key, val in other.items()\n        }\n\n    def __ne__(self, other):\n        return not (self == other)\n\n    #\n    # The remaining methods have slow default\n    # implementations for MutableMapping. In particular,\n    # they rely KeyError catching, which is slow for this\n    # class because KeyError messages use fully qualified\n    # names.\n    #\n\n    def __contains__(self, obj):\n        return id(obj) in self._dict\n\n    def clear(self):\n        'D.clear() -> None.  Remove all items from D.'\n        self._dict.clear()\n\n    def get(self, key, default=None):\n        'D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None.'\n        if key in self:\n            return self[key]\n        return default\n\n    def setdefault(self, key, default=None):\n        'D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D'\n        if key in self:\n            return self[key]\n        else:\n            self[key] = default\n        return default",
  "start_line": 1,
  "end_line": 135,
  "total_lines": 135,
  "is_truncated": false
}
Generated tokens 207 tokens · stopped: STOP
In `_diff_GeneralExpression`: ```python def _diff_GeneralExpression(node, val_dict, der_dict): """ Reverse automatic differentiation for named expressions. Parameters ---------- node: The named expression val_dict: ComponentMap der_dict: ComponentMap """ der_dict[node.expr] += der_dict[node] ``` The `node` here is a named expression (e.g., `m.y` which is an `Expression` object). `node.expr` is the expression it represents. In the reproduction case, `m.y` returns `2`. So `node.expr` is `2`. `der_dict` is a `ComponentMap`. Let's see how `ComponentMap` is implemented. <channel|><|tool_call>call:read_file{filepath:<|"|>pyomo/common/collections/component_map.py<|"|>}<tool_call|><|tool_response>
Turn 5at 116 s453 tokens out9,160 prompt tokens
`ComponentMap` uses `id(obj)` as keys. This is intended to avoid hashing subclasses of `NumericValue`. However, if `obj` is a simple python float or int, `id(obj)` is still used.

In `_diff_GeneralExpression`:
`der_dict[node.expr] += der_dict[node]`

If `node` is an `Expression` that evaluates to a constant (like `2`), then `node.expr` is `2` (or `2.0`).
When `der_dict[node.expr]` is called, it triggers `__getitem__` in `ComponentMap`.
If `2.0` is not already in `der_dict`, `ComponentMap.__getitem__` raises a `KeyError`.

Wait, `der_dict[node.expr] += der_dict[node]` is doing a read and then a write.
`der_dict[node.expr] = der_dict[node.expr] + der_dict[node]`

The read `der_dict[node.expr]` fails if `node.expr` is not in the map.

But for a constant expression, the derivative should be 0.
In reverse mode AD, `der_dict[node]` represents the derivative of the final output with respect to `node`.
If `node` is an expression `y = 2`, then $\frac{\partial y}{\partial x} = 0$.
However, `node` is being used as a node in the computational graph.

Let's see how `der_dict` is initialized and used.
`_reverse_diff_helper` calls `_diff_GeneralExpression`.

Let's read `_reverse_diff_helper` and `reverse_sd` in `pyomo/core/expr/calculus/diff_with_pyomo.py`.
TOOL CALL · read_file
{
  "end_line": 484,
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "start_line": 400
}
Result of read_file 2,641 characters
{
  "status": "ok",
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "content": "            self.operation_func = _numeric_apply_operation\n        else:\n            self.value_func = _symbolic_value\n            self.operation_func = _symbolic_apply_operation\n\n    def visit(self, node, values):\n        self.val_dict[node] = self.operation_func(node, values)\n        self.der_dict[node] = 0\n        self.expr_list.append(node)\n        return self.val_dict[node]\n\n    def visiting_potential_leaf(self, node):\n        if node in self.val_dict:\n            return True, self.val_dict[node]\n\n        if node.__class__ in nonpyomo_leaf_types:\n            self.val_dict[node] = node\n            self.der_dict[node] = 0\n            return True, node\n\n        if not node.is_expression_type():\n            val = self.value_func(node)\n            self.val_dict[node] = val\n            self.der_dict[node] = 0\n            return True, val\n\n        return False, None\n\n\ndef _reverse_diff_helper(expr, numeric=True):\n    val_dict = ComponentMap()\n    der_dict = ComponentMap()\n    expr_list = list()\n\n    visitorA = _LeafToRootVisitor(val_dict, der_dict, expr_list, numeric=numeric)\n    visitorA.dfs_postorder_stack(expr)\n\n    der_dict[expr] = 1\n    for e in reversed(expr_list):\n        if e.__class__ in _diff_map:\n            _diff_map[e.__class__](e, val_dict, der_dict)\n        elif e.is_named_expression_type():\n            _diff_GeneralExpression(e, val_dict, der_dict)\n        else:\n            raise DifferentiationException(\n                'Unsupported expression type for differentiation: {0}'.format(type(e))\n            )\n\n    return der_dict\n\n\ndef reverse_ad(expr):\n    \"\"\"\n    First order reverse automatic differentiation\n\n    Parameters\n    ----------\n    expr: pyomo.core.expr.numeric_expr.NumericExpression\n        expression to differentiate\n\n    Returns\n    -------\n    ComponentMap\n        component_map mapping variables to derivatives with respect\n        to the corresponding variable\n    \"\"\"\n    return _reverse_diff_helper(expr, True)\n\n\ndef reverse_sd(expr):\n    \"\"\"\n    First order reverse symbolic differentiation\n\n    Parameters\n    ----------\n    expr: pyomo.core.expr.numeric_expr.NumericExpression\n        expression to differentiate\n\n    Returns\n    -------\n    ComponentMap\n        component_map mapping variables to derivatives with respect\n        to the corresponding variable\n    \"\"\"\n    return _reverse_diff_helper(expr, False)",
  "start_line": 400,
  "end_line": 484,
  "total_lines": 484,
  "is_truncated": false
}
Generated tokens 453 tokens · stopped: STOP
`ComponentMap` uses `id(obj)` as keys. This is intended to avoid hashing subclasses of `NumericValue`. However, if `obj` is a simple python float or int, `id(obj)` is still used. In `_diff_GeneralExpression`: `der_dict[node.expr] += der_dict[node]` If `node` is an `Expression` that evaluates to a constant (like `2`), then `node.expr` is `2` (or `2.0`). When `der_dict[node.expr]` is called, it triggers `__getitem__` in `ComponentMap`. If `2.0` is not already in `der_dict`, `ComponentMap.__getitem__` raises a `KeyError`. Wait, `der_dict[node.expr] += der_dict[node]` is doing a read and then a write. `der_dict[node.expr] = der_dict[node.expr] + der_dict[node]` The read `der_dict[node.expr]` fails if `node.expr` is not in the map. But for a constant expression, the derivative should be 0. In reverse mode AD, `der_dict[node]` represents the derivative of the final output with respect to `node`. If `node` is an expression `y = 2`, then $\frac{\partial y}{\partial x} = 0$. However, `node` is being used as a node in the computational graph. Let's see how `der_dict` is initialized and used. `_reverse_diff_helper` calls `_diff_GeneralExpression`. Let's read `_reverse_diff_helper` and `reverse_sd` in `pyomo/core/expr/calculus/diff_with_pyomo.py`. <channel|><|tool_call>call:read_file{end_line:484,filepath:<|"|>pyomo/core/expr/calculus/diff_with_pyomo.py<|"|>,start_line:400}<tool_call|><|tool_response>
Turn 6at 127 s168 tokens out10,419 prompt tokens
In `_reverse_diff_helper`:
1. `_LeafToRootVisitor` is used to compute values and initialize `der_dict`.
2. `der_dict[expr] = 1` (seed for reverse mode).
3. For each expression `e` in reverse postorder:
    - If `e` is in `_diff_map`, call the diff function.
    - Else if `e` is a named expression, call `_diff_GeneralExpression`.

Let's see `_LeafToRootVisitor`.
TOOL CALL · read_file
{
  "end_line": 420,
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "start_line": 350
}
Result of read_file 2,809 characters
{
  "status": "ok",
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "content": "_diff_map = dict()\n_diff_map[_expr.ProductExpression] = _diff_ProductExpression\n_diff_map[_expr.DivisionExpression] = _diff_DivisionExpression\n_diff_map[_expr.PowExpression] = _diff_PowExpression\n_diff_map[_expr.SumExpression] = _diff_SumExpression\n_diff_map[_expr.MonomialTermExpression] = _diff_ProductExpression\n_diff_map[_expr.NegationExpression] = _diff_NegationExpression\n_diff_map[_expr.UnaryFunctionExpression] = _diff_UnaryFunctionExpression\n_diff_map[_expr.ExternalFunctionExpression] = _diff_ExternalFunctionExpression\n_diff_map[_expr.LinearExpression] = _diff_SumExpression\n_diff_map[_expr.AbsExpression] = _diff_abs\n\n_diff_map[_expr.NPV_ProductExpression] = _diff_ProductExpression\n_diff_map[_expr.NPV_DivisionExpression] = _diff_DivisionExpression\n_diff_map[_expr.NPV_PowExpression] = _diff_PowExpression\n_diff_map[_expr.NPV_SumExpression] = _diff_SumExpression\n_diff_map[_expr.NPV_NegationExpression] = _diff_NegationExpression\n_diff_map[_expr.NPV_UnaryFunctionExpression] = _diff_UnaryFunctionExpression\n_diff_map[_expr.NPV_ExternalFunctionExpression] = _diff_ExternalFunctionExpression\n_diff_map[_expr.NPV_AbsExpression] = _diff_abs\n\n\ndef _symbolic_value(x):\n    return x\n\n\ndef _numeric_apply_operation(node, values):\n    return node._apply_operation(values)\n\n\ndef _symbolic_apply_operation(node, values):\n    return node\n\n\nclass _LeafToRootVisitor(ExpressionValueVisitor):\n    def __init__(self, val_dict, der_dict, expr_list, numeric=True):\n        \"\"\"\n        Parameters\n        ----------\n        val_dict: ComponentMap\n        der_dict: ComponentMap\n        \"\"\"\n        self.val_dict = val_dict\n        self.der_dict = der_dict\n        self.expr_list = expr_list\n        assert len(self.expr_list) == 0\n        assert len(self.val_dict) == 0\n        assert len(self.der_dict) == 0\n        if numeric:\n            self.value_func = value\n            self.operation_func = _numeric_apply_operation\n        else:\n            self.value_func = _symbolic_value\n            self.operation_func = _symbolic_apply_operation\n\n    def visit(self, node, values):\n        self.val_dict[node] = self.operation_func(node, values)\n        self.der_dict[node] = 0\n        self.expr_list.append(node)\n        return self.val_dict[node]\n\n    def visiting_potential_leaf(self, node):\n        if node in self.val_dict:\n            return True, self.val_dict[node]\n\n        if node.__class__ in nonpyomo_leaf_types:\n            self.val_dict[node] = node\n            self.der_dict[node] = 0\n            return True, node\n\n        if not node.is_expression_type():",
  "start_line": 350,
  "end_line": 420,
  "total_lines": 484,
  "is_truncated": false
}
Generated tokens 168 tokens · stopped: STOP
In `_reverse_diff_helper`: 1. `_LeafToRootVisitor` is used to compute values and initialize `der_dict`. 2. `der_dict[expr] = 1` (seed for reverse mode). 3. For each expression `e` in reverse postorder: - If `e` is in `_diff_map`, call the diff function. - Else if `e` is a named expression, call `_diff_GeneralExpression`. Let's see `_LeafToRootVisitor`. <channel|><|tool_call>call:read_file{end_line:420,filepath:<|"|>pyomo/core/expr/calculus/diff_with_pyomo.py<|"|>,start_line:350}<tool_call|><|tool_response>
Turn 7at 201 s1,261 tokens out11,506 prompt tokens
In `_LeafToRootVisitor.visit`:
```python
    def visit(self, node, values):
        self.val_dict[node] = self.operation_func(node, values)
        self.der_dict[node] = 0
        self.expr_list.append(node)
        return self.val_dict[node]
```
This initializes `der_dict[node] = 0` for every `node` visited during the postorder traversal.

However, `_diff_GeneralExpression` does:
`der_dict[node.expr] += der_dict[node]`

If `node.expr` is a constant value (like `2.0`), it was never visited as a `node` itself in the traversal if it was just returned as a value by another expression.

Actually, `node` in `_diff_GeneralExpression` is a `GeneralExpression` (named expression).
In the reproduction:
`m.y` is a `GeneralExpression` that returns `2`.

When `_LeafToRootVisitor` visits `m.y`:
`node` is `m.y`. `self.operation_func(node, values)` returns `2`.
So `self.val_dict[m.y] = 2` and `self.der_dict[m.y] = 0`.

Then in `_reverse_diff_helper`, we call `_diff_GeneralExpression(m.y, val_dict, der_dict)`.
`node` is `m.y`. `node.expr` is `2`.
`der_dict[node.expr] += der_dict[node]` -> `der_dict[2] += der_dict[m.y]`.
But `2` is not in `der_dict`.

If `node.expr` is a constant, it should not be in `der_dict` because it's not a variable or a named expression that can be differentiated with respect to. Or rather, if it's a constant, the derivative of the output with respect to this constant should be 0, and it doesn't propagate back to any variables.

Wait, if `node.expr` is a constant, then `der_dict[node.expr]` would only be needed if we wanted the derivative with respect to that constant. But we usually only care about derivatives with respect to variables.

Wait, `der_dict[node.expr] += der_dict[node]` is trying to propagate the gradient from the named expression `node` to the expression it represents `node.expr`. If `node.expr` is a constant, this propagation should simply stop or be ignored because constants have zero derivative.

However, if `node.expr` is another complex expression, it would be in `der_dict` (unless it's a constant).

If `node.expr` is a constant, we can just skip this.

Let's verify what `node.expr` can be. For a named expression `m.y = 2`, `node.expr` is `2`. For `m.y = m.x * 2`, `node.expr` is the product expression.

If `node.expr` is a constant, then `der_dict[node.expr]` is not needed because constants are leaf nodes in the differentiation graph that don't contribute to any variable derivatives.

But the current implementation of `ComponentMap` doesn't support constants well if they are not already in the map.

Actually, if `node.expr` is a constant, then $\frac{\partial \text{Output}}{\partial \text{Constant}} = 0$ is not what's being computed here. `der_dict` stores $\frac{\partial \text{Output}}{\partial \text{node}}$.
If $y = \text{expr}(x)$, then $\frac{\partial \text{Output}}{\partial x} = \frac{\partial \text{Output}}{\partial y} \frac{\partial y}{\partial x}$.
`der_dict[node]` is $\frac{\partial \text{Output}}{\partial y}$.
`der_dict[node.expr]` should be updated with $\frac{\partial \text{Output}}{\partial y} \cdot 1$.

If `node.expr` is a constant, then $\frac{\partial y}{\partial \text{anything}} = 0$.

Let's see if we can just check if `node.expr` is a constant before doing the addition.

Wait, what if `node.expr` is a Pyomo component (Variable, etc.)? It would be in `der_dict` if it was visited.

In `_LeafToRootVisitor.visiting_potential_leaf`:
```python
    def visiting_potential_leaf(self, node):
        if node in self.val_dict:
            return True, self.val_dict[node]

        if node.__class__ in nonpyomo_leaf_types:
            self.val_dict[node] = node
            self.der_dict[node] = 0
            return True, node

        if not node.is_expression_type():
            val = self.value_func(node)
            self.val_dict[node] = val
            self.der_dict[node] = 0
            return True, val

        return False, None
```
`nonpyomo_leaf_types` likely includes `int` and `float`. Let's check `nonpyomo_leaf_types`.
TOOL CALL · read_file
{
  "end_line": 100,
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "start_line": 1
}
Result of read_file 3,381 characters
{
  "status": "ok",
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "content": "#  ___________________________________________________________________________\n#\n#  Pyomo: Python Optimization Modeling Objects\n#  Copyright (c) 2008-2022\n#  National Technology and Engineering Solutions of Sandia, LLC\n#  Under the terms of Contract DE-NA0003525 with National Technology and\n#  Engineering Solutions of Sandia, LLC, the U.S. Government retains certain\n#  rights in this software.\n#  This software is distributed under the 3-clause BSD License.\n#  ___________________________________________________________________________\n\nfrom pyomo.common.collections import ComponentMap, ComponentSet\nimport pyomo.core.expr as _expr\nfrom pyomo.core.expr.visitor import ExpressionValueVisitor, nonpyomo_leaf_types\nfrom pyomo.core.expr.numvalue import value, is_constant\nfrom pyomo.core.expr import exp, log, sin, cos\nimport math\n\n\n\"\"\"\nThe purpose of this file is to perform symbolic differentiation and \nfirst order automatic differentiation directly with pyomo \nexpressions. This is certainly not as efficient as doing AD in C or \nC++, but it avoids the translation from pyomo expressions to a form \nwhere AD can be performed efficiently. The only functions that are \nmeant to be used by users are reverse_ad and reverse_sd. First, \nvalues are propagated from the leaves to each node in the tree with \nthe LeafToRoot visitors. Then derivative values are propagated from \nthe root to the leaves with the RootToLeaf visitors.\n\"\"\"\n\n\nclass DifferentiationException(Exception):\n    pass\n\n\ndef _diff_ProductExpression(node, val_dict, der_dict):\n    \"\"\"\n\n    Parameters\n    ----------\n    node: pyomo.core.expr.numeric_expr.ProductExpression\n    val_dict: ComponentMap\n    der_dict: ComponentMap\n    \"\"\"\n    assert len(node.args) == 2\n    arg1, arg2 = node.args\n    der = der_dict[node]\n    der_dict[arg1] += der * val_dict[arg2]\n    der_dict[arg2] += der * val_dict[arg1]\n\n\ndef _diff_SumExpression(node, val_dict, der_dict):\n    \"\"\"\n\n    Parameters\n    ----------\n    node: pyomo.core.expr.numeric_expr.SumExpression\n    val_dict: ComponentMap\n    der_dict: ComponentMap\n    \"\"\"\n    der = der_dict[node]\n    for arg in node.args:\n        der_dict[arg] += der\n\n\ndef _diff_PowExpression(node, val_dict, der_dict):\n    \"\"\"\n\n    Parameters\n    ----------\n    node: pyomo.core.expr.numeric_expr.PowExpression\n    val_dict: ComponentMap\n    der_dict: ComponentMap\n    \"\"\"\n    assert len(node.args) == 2\n    arg1, arg2 = node.args\n    der = der_dict[node]\n    val1 = val_dict[arg1]\n    val2 = val_dict[arg2]\n    der_dict[arg1] += der * val2 * val1 ** (val2 - 1)\n    if arg2.__class__ not in nonpyomo_leaf_types:\n        der_dict[arg2] += der * val1**val2 * log(val1)\n\n\ndef _diff_DivisionExpression(node, val_dict, der_dict):\n    \"\"\"\n\n    Parameters\n    ----------\n    node: pyomo.core.expr.numeric_expr.DivisionExpression\n    val_dict: ComponentMap\n    der_dict: ComponentMap\n    \"\"\"\n    assert len(node.args) == 2\n    num = node.args[0]\n    den = node.args[1]\n    der = der_dict[node]\n    der_dict[num] += der * (1 / val_dict[den])\n    der_dict[den] -= der * val_dict[num] / val_dict[den] ** 2",
  "start_line": 1,
  "end_line": 100,
  "total_lines": 484,
  "is_truncated": false
}
Generated tokens 1,261 tokens · stopped: STOP
In `_LeafToRootVisitor.visit`: ```python def visit(self, node, values): self.val_dict[node] = self.operation_func(node, values) self.der_dict[node] = 0 self.expr_list.append(node) return self.val_dict[node] ``` This initializes `der_dict[node] = 0` for every `node` visited during the postorder traversal. However, `_diff_GeneralExpression` does: `der_dict[node.expr] += der_dict[node]` If `node.expr` is a constant value (like `2.0`), it was never visited as a `node` itself in the traversal if it was just returned as a value by another expression. Actually, `node` in `_diff_GeneralExpression` is a `GeneralExpression` (named expression). In the reproduction: `m.y` is a `GeneralExpression` that returns `2`. When `_LeafToRootVisitor` visits `m.y`: `node` is `m.y`. `self.operation_func(node, values)` returns `2`. So `self.val_dict[m.y] = 2` and `self.der_dict[m.y] = 0`. Then in `_reverse_diff_helper`, we call `_diff_GeneralExpression(m.y, val_dict, der_dict)`. `node` is `m.y`. `node.expr` is `2`. `der_dict[node.expr] += der_dict[node]` -> `der_dict[2] += der_dict[m.y]`. But `2` is not in `der_dict`. If `node.expr` is a constant, it should not be in `der_dict` because it's not a variable or a named expression that can be differentiated with respect to. Or rather, if it's a constant, the derivative of the output with respect to this constant should be 0, and it doesn't propagate back to any variables. Wait, if `node.expr` is a constant, then `der_dict[node.expr]` would only be needed if we wanted the derivative with respect to that constant. But we usually only care about derivatives with respect to variables. Wait, `der_dict[node.expr] += der_dict[node]` is trying to propagate the gradient from the named expression `node` to the expression it represents `node.expr`. If `node.expr` is a constant, this propagation should simply stop or be ignored because constants have zero derivative. However, if `node.expr` is another complex expression, it would be in `der_dict` (unless it's a constant). If `node.expr` is a constant, we can just skip this. Let's verify what `node.expr` can be. For a named expression `m.y = 2`, `node.expr` is `2`. For `m.y = m.x * 2`, `node.expr` is the product expression. If `node.expr` is a constant, then `der_dict[node.expr]` is not needed because constants are leaf nodes in the differentiation graph that don't contribute to any variable derivatives. But the current implementation of `ComponentMap` doesn't support constants well if they are not already in the map. Actually, if `node.expr` is a constant, then $\frac{\partial \text{Output}}{\partial \text{Constant}} = 0$ is not what's being computed here. `der_dict` stores $\frac{\partial \text{Output}}{\partial \text{node}}$. If $y = \text{expr}(x)$, then $\frac{\partial \text{Output}}{\partial x} = \frac{\partial \text{Output}}{\partial y} \frac{\partial y}{\partial x}$. `der_dict[node]` is $\frac{\partial \text{Output}}{\partial y}$. `der_dict[node.expr]` should be updated with $\frac{\partial \text{Output}}{\partial y} \cdot 1$. If `node.expr` is a constant, then $\frac{\partial y}{\partial \text{anything}} = 0$. Let's see if we can just check if `node.expr` is a constant before doing the addition. Wait, what if `node.expr` is a Pyomo component (Variable, etc.)? It would be in `der_dict` if it was visited. In `_LeafToRootVisitor.visiting_potential_leaf`: ```python def visiting_potential_leaf(self, node): if node in self.val_dict: return True, self.val_dict[node] if node.__class__ in nonpyomo_leaf_types: self.val_dict[node] = node self.der_dict[node] = 0 return True, node if not node.is_expression_type(): val = self.value_func(node) self.val_dict[node] = val self.der_dict[node] = 0 return True, val return False, None ``` `nonpyomo_leaf_types` likely includes `int` and `float`. Let's check `nonpyomo_leaf_types`. <channel|><|tool_call>call:read_file{end_line:100,filepath:<|"|>pyomo/core/expr/calculus/diff_with_pyomo.py<|"|>,start_line:1}<tool_call|><|tool_response>
Turn 8at 214 s200 tokens out13,853 prompt tokens
It imports `nonpyomo_leaf_types` from `pyomo.core.expr.visitor`. And it imports `is_constant` from `pyomo.core.expr.numvalue`.

If `node.expr` is a constant, we can skip updating `der_dict[node.expr]`.

Wait, if `node.expr` is a constant, and it is not in `der_dict`, we have a `KeyError`.
If we use `is_constant(node.expr)`, we can avoid this.

Let's see if `is_constant` works for python floats/ints.
TOOL CALL · run_command
{
  "command": "python3 - <<'PY'\nfrom pyomo.core.expr.numvalue import is_constant\nprint(f\"{is_constant(2)=}\")\nprint(f\"{is_constant(2.0)=}\")\nPY\n"
}
Result of run_command 104 characters
{
  "status": "ok",
  "stdout": "is_constant(2)=True\nis_constant(2.0)=True\n",
  "stderr": "",
  "exit_code": 0
}
Generated tokens 200 tokens · stopped: STOP
It imports `nonpyomo_leaf_types` from `pyomo.core.expr.visitor`. And it imports `is_constant` from `pyomo.core.expr.numvalue`. If `node.expr` is a constant, we can skip updating `der_dict[node.expr]`. Wait, if `node.expr` is a constant, and it is not in `der_dict`, we have a `KeyError`. If we use `is_constant(node.expr)`, we can avoid this. Let's see if `is_constant` works for python floats/ints. <channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY' from pyomo.core.expr.numvalue import is_constant print(f"{is_constant(2)=}") print(f"{is_constant(2.0)=}") PY <|"|>}<tool_call|><|tool_response>
Turn 9at 358 s2,356 tokens out14,110 prompt tokens
So `is_constant` is perfect.

Let's modify `_diff_GeneralExpression` in `pyomo/core/expr/calculus/diff_with_pyomo.py` to check if `node.expr` is constant.

```python
def _diff_GeneralExpression(node, val_dict, der_dict):
    """
    Reverse automatic differentiation for named expressions.

    Parameters
    ----------
    node: The named expression
    val_dict: ComponentMap
    der_dict: ComponentMap
    """
    der_dict[node.expr] += der_dict[node]
```

To:

```python
def _diff_GeneralExpression(node, val_dict, der_dict):
    """
    Reverse automatic differentiation for named expressions.

    Parameters
    ----------
    node: The named expression
    val_dict: ComponentMap
    der_dict: ComponentMap
    """
    if not is_constant(node.expr):
        der_dict[node.expr] += der_dict[node]
```

Wait, if `node.expr` is not a constant, it SHOULD be in `der_dict` because `_LeafToRootVisitor` visits all expressions in the graph.

Let's double check `_LeafToRootVisitor` again.

```python
class _LeafToRootVisitor(ExpressionValueVisitor):
    # ...
    def visit(self, node, values):
        self.val_dict[node] = self.operation_func(node, values)
        self.der_dict[node] = 0
        self.expr_list.append(node)
        return self.val_dict[node]
```

`ExpressionValueVisitor`'s `visit` method usually handles the traversal.

If `node` is a named expression, its `.expr` is the underlying expression.
If `node.expr` is not a constant, it's a `NumericExpression`.
The visitor should have visited it.

Wait, if `node` is the named expression, is `node.expr` visited separately?

In `_LeafToRootVisitor.visit(node, values)`, `node` is visited.
If `node` is a `GeneralExpression`, then `node.expr` is its underlying expression.
Does `ExpressionValueVisitor` visit `node.expr` when visiting a `GeneralExpression`?

Let's check `pyomo/core/expr/visitor.py` or similar. But `ExpressionValueVisitor` is a base class.

Actually, if `node` is a `GeneralExpression`, the visitor might not automatically visit `node.expr`.

Let's check how `GeneralExpression` is handled in `ExpressionValueVisitor`.

Wait, I don't see `GeneralExpression` explicitly handled in the provided code snippets, but `_diff_GeneralExpression` is called when `e.is_named_expression_type()` is true.

If `node.expr` was not visited, then `der_dict[node.expr]` would fail even if it's not a constant.

Let's test this hypothesis. If I have `m.y = m.x * 2`, then `m.y` is a `GeneralExpression` and `m.y.expr` is a `ProductExpression`. If the visitor doesn't visit the `ProductExpression` through `m.y`, it will fail.

Wait, in the reproduction case, `m.product` is also a `GeneralExpression`.
`m.product.expr` is `m.x * m.y`.
`m.y` is also a `GeneralExpression`.

If `m.product` is visited, `_LeafToRootVisitor` visits it.
If `m.product` behaves like a normal expression, the visitor follows its args.
But `GeneralExpression` is a wrapper.

Let's see what `GeneralExpression` is. It's probably in `pyomo/core/expr/numeric_expr.py` or similar.

Actually, the issue is that `node.expr` (the constant `2.0`) is not in `der_dict`.
If `node.expr` is a constant, we don't need to propagate the derivative to it.
If `node.expr` is NOT a constant, it must be in `der_dict`. Why?
Because the `ExpressionValueVisitor` should have visited it.

Let's check if `GeneralExpression` is handled by `ExpressionValueVisitor`.

Actually, let's just try the fix and see if it passes the reproduction and doesn't break other things.

The reproduction case is:
`m.y = 2`
`m.product = m.x * m.y`
`differentiate(m.product, wrt=m.x)`

`m.product` is a `GeneralExpression`. Its `.expr` is `m.x * m.y`.
`m.y` is a `GeneralExpression`. Its `.expr` is `2`.

When differentiating `m.product`:
1. Visitor visits `m.product`.
2. Visitor visits `m.product.expr` (the ProductExpression).
3. Visitor visits args of ProductExpression: `m.x` and `m.y`.
4. When visiting `m.y`, the visitor sees it's a `GeneralExpression`.
Does it visit `m.y.expr`?
If it does, then `m.y.expr` (which is `2`) is visited.
In `visiting_potential_leaf(m.y.expr)`:
`2` is in `nonpyomo_leaf_types`.
So `self.val_dict[2] = 2` and `self.der_dict[2] = 0`.
Wait! If this happened, `der_dict[2]` would be initialized to 0, and the `KeyError` wouldn't happen!

So `m.y.expr` (the constant `2`) is NOT being visited by the visitor when `m.y` is visited.

This means `GeneralExpression` is NOT being unpacked by the visitor.

But wait, `_diff_GeneralExpression` is explicitly called:
```python
        elif e.is_named_expression_type():
            _diff_GeneralExpression(e, val_dict, der_dict)
```
This is for the reverse pass.

What about the forward pass (`_LeafToRootVisitor`)?
If `e` is a `GeneralExpression`, `_LeafToRootVisitor.visit(e, values)` is called.
```python
    def visit(self, node, values):
        self.val_dict[node] = self.operation_func(node, values)
        self.der_dict[node] = 0
        self.expr_list.append(node)
        return self.val_dict[node]
```
`self.operation_func(node, values)` for a `GeneralExpression` in symbolic mode is `_symbolic_value(node)` which returns `node`.
Wait, no. `_symbolic_value` is:
```python
def _symbolic_value(x):
    return x
```
So `val_dict[m.y] = m.y`.
And `der_dict[m.y] = 0`.
And `m.y` is added to `expr_list`.
But `m.y.expr` is NEVER visited because the visitor doesn't know it should visit `node.expr` for `GeneralExpression`s.

This seems wrong if we want to differentiate THROUGH named expressions. But if we are differentiating with respect to `m.x`, and `m.product = m.x * m.y`, then:
$\frac{\partial \text{product}}{\partial x} = \frac{\partial \text{product}}{\partial x} \cdot 1 + \frac{\partial \text{product}}{\partial y} \frac{\partial y}{\partial x}$.
Since $y=2$, $\frac{\partial y}{\partial x} = 0$.

The reverse pass does:
1. `der_dict[m.product] = 1`
2. `_diff_GeneralExpression(m.product, ...)` -> `der_dict[m.product.expr] += der_dict[m.product]`
   Now `der_dict[m.x * m.y] = 1`.
3. `_diff_ProductExpression(m.x * m.y, ...)` ->
   `der_dict[m.x] += 1 * val_dict[m.y]`
   `der_dict[m.y] += 1 * val_dict[m.x]`
   Now `der_dict[m.x] = 2` (if `m.y=2`) and `der_dict[m.y] = m.x`.
4. `_diff_GeneralExpression(m.y, ...)` -> `der_dict[m.y.expr] += der_dict[m.y]`
   Since `m.y.expr = 2`, this is `der_dict[2] += der_dict[m.y]`.
   And here we get the `KeyError` because `2` was never visited in the forward pass.

If `m.y.expr` is a constant, then `der_dict[2]` doesn't need to be updated because it won't affect any variable's derivative.

So adding the `is_constant` check should fix this.

Let's try applying the fix.
TOOL CALL · edit_file
{
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "new_string": "def _diff_GeneralExpression(node, val_dict, der_dict):\n    \\\"\\\"\\\"\n    Reverse automatic differentiation for named expressions.\n\n    Parameters\n    ----------\n    node: The named expression\n    val_dict: ComponentMap\n    der_dict: ComponentMap\n    \\\"\\\"\\\"\n    if not is_constant(node.expr):\n        der_dict[node.expr] += der_dict[node]\n",
  "old_string": "def _diff_GeneralExpression(node, val_dict, der_dict):\n    \\\"\\\"\\\"\n    Reverse automatic differentiation for named expressions.\n\n    Parameters\n    ----------\n    node: The named expression\n    val_dict: ComponentMap\n    der_dict: ComponentMap\n    \\\"\\\"\\\"\n    der_dict[node.expr] += der_dict[node]\n"
}
Result of edit_file 548 characters
{
  "status": "ok",
  "filepath": "pyomo/core/expr/calculus/diff_with_pyomo.py",
  "occurrences": 1,
  "strategy": "unescaped",
  "diff": "--- a/pyomo/core/expr/calculus/diff_with_pyomo.py\n+++ b/pyomo/core/expr/calculus/diff_with_pyomo.py\n@@ -328,7 +328,8 @@\n     val_dict: ComponentMap\n     der_dict: ComponentMap\n     \"\"\"\n-    der_dict[node.expr] += der_dict[node]\n+    if not is_constant(node.expr):\n+        der_dict[node.expr] += der_dict[node]\n \n \n def _diff_ExternalFunctionExpression(node, val_dict, der_dict):\n",
  "is_truncated": false
}
Generated tokens 2,356 tokens · stopped: STOP
So `is_constant` is perfect. Let's modify `_diff_GeneralExpression` in `pyomo/core/expr/calculus/diff_with_pyomo.py` to check if `node.expr` is constant. ```python def _diff_GeneralExpression(node, val_dict, der_dict): """ Reverse automatic differentiation for named expressions. Parameters ---------- node: The named expression val_dict: ComponentMap der_dict: ComponentMap """ der_dict[node.expr] += der_dict[node] ``` To: ```python def _diff_GeneralExpression(node, val_dict, der_dict): """ Reverse automatic differentiation for named expressions. Parameters ---------- node: The named expression val_dict: ComponentMap der_dict: ComponentMap """ if not is_constant(node.expr): der_dict[node.expr] += der_dict[node] ``` Wait, if `node.expr` is not a constant, it SHOULD be in `der_dict` because `_LeafToRootVisitor` visits all expressions in the graph. Let's double check `_LeafToRootVisitor` again. ```python class _LeafToRootVisitor(ExpressionValueVisitor): # ... def visit(self, node, values): self.val_dict[node] = self.operation_func(node, values) self.der_dict[node] = 0 self.expr_list.append(node) return self.val_dict[node] ``` `ExpressionValueVisitor`'s `visit` method usually handles the traversal. If `node` is a named expression, its `.expr` is the underlying expression. If `node.expr` is not a constant, it's a `NumericExpression`. The visitor should have visited it. Wait, if `node` is the named expression, is `node.expr` visited separately? In `_LeafToRootVisitor.visit(node, values)`, `node` is visited. If `node` is a `GeneralExpression`, then `node.expr` is its underlying expression. Does `ExpressionValueVisitor` visit `node.expr` when visiting a `GeneralExpression`? Let's check `pyomo/core/expr/visitor.py` or similar. But `ExpressionValueVisitor` is a base class. Actually, if `node` is a `GeneralExpression`, the visitor might not automatically visit `node.expr`. Let's check how `GeneralExpression` is handled in `ExpressionValueVisitor`. Wait, I don't see `GeneralExpression` explicitly handled in the provided code snippets, but `_diff_GeneralExpression` is called when `e.is_named_expression_type()` is true. If `node.expr` was not visited, then `der_dict[node.expr]` would fail even if it's not a constant. Let's test this hypothesis. If I have `m.y = m.x * 2`, then `m.y` is a `GeneralExpression` and `m.y.expr` is a `ProductExpression`. If the visitor doesn't visit the `ProductExpression` through `m.y`, it will fail. Wait, in the reproduction case, `m.product` is also a `GeneralExpression`. `m.product.expr` is `m.x * m.y`. `m.y` is also a `GeneralExpression`. If `m.product` is visited, `_LeafToRootVisitor` visits it. If `m.product` behaves like a normal expression, the visitor follows its args. But `GeneralExpression` is a wrapper. Let's see what `GeneralExpression` is. It's probably in `pyomo/core/expr/numeric_expr.py` or similar. Actually, the issue is that `node.expr` (the constant `2.0`) is not in `der_dict`. If `node.expr` is a constant, we don't need to propagate the derivative to it. If `node.expr` is NOT a constant, it must be in `der_dict`. Why? Because the `ExpressionValueVisitor` should have visited it. Let's check if `GeneralExpression` is handled by `ExpressionValueVisitor`. Actually, let's just try the fix and see if it passes the reproduction and doesn't break other things. The reproduction case is: `m.y = 2` `m.product = m.x * m.y` `differentiate(m.product, wrt=m.x)` `m.product` is a `GeneralExpression`. Its `.expr` is `m.x * m.y`. `m.y` is a `GeneralExpression`. Its `.expr` is `2`. When differentiating `m.product`: 1. Visitor visits `m.product`. 2. Visitor visits `m.product.expr` (the ProductExpression). 3. Visitor visits args of ProductExpression: `m.x` and `m.y`. 4. When visiting `m.y`, the visitor sees it's a `GeneralExpression`. Does it visit `m.y.expr`? If it does, then `m.y.expr` (which is `2`) is visited. In `visiting_potential_leaf(m.y.expr)`: `2` is in `nonpyomo_leaf_types`. So `self.val_dict[2] = 2` and `self.der_dict[2] = 0`. Wait! If this happened, `der_dict[2]` would be initialized to 0, and the `KeyError` wouldn't happen! So `m.y.expr` (the constant `2`) is NOT being visited by the visitor when `m.y` is visited. This means `GeneralExpression` is NOT being unpacked by the visitor. But wait, `_diff_GeneralExpression` is explicitly called: ```python elif e.is_named_expression_type(): _diff_GeneralExpression(e, val_dict, der_dict) ``` This is for the reverse pass. What about the forward pass (`_LeafToRootVisitor`)? If `e` is a `GeneralExpression`, `_LeafToRootVisitor.visit(e, values)` is called. ```python def visit(self, node, values): self.val_dict[node] = self.operation_func(node, values) self.der_dict[node] = 0 self.expr_list.append(node) return self.val_dict[node] ``` `self.operation_func(node, values)` for a `GeneralExpression` in symbolic mode is `_symbolic_value(node)` which returns `node`. Wait, no. `_symbolic_value` is: ```python def _symbolic_value(x): return x ``` So `val_dict[m.y] = m.y`. And `der_dict[m.y] = 0`. And `m.y` is added to `expr_list`. But `m.y.expr` is NEVER visited because the visitor doesn't know it should visit `node.expr` for `GeneralExpression`s. This seems wrong if we want to differentiate THROUGH named expressions. But if we are differentiating with respect to `m.x`, and `m.product = m.x * m.y`, then: $\frac{\partial \text{product}}{\partial x} = \frac{\partial \text{product}}{\partial x} \cdot 1 + \frac{\partial \text{product}}{\partial y} \frac{\partial y}{\partial x}$. Since $y=2$, $\frac{\partial y}{\partial x} = 0$. The reverse pass does: 1. `der_dict[m.product] = 1` 2. `_diff_GeneralExpression(m.product, ...)` -> `der_dict[m.product.expr] += der_dict[m.product]` Now `der_dict[m.x * m.y] = 1`. 3. `_diff_ProductExpression(m.x * m.y, ...)` -> `der_dict[m.x] += 1 * val_dict[m.y]` `der_dict[m.y] += 1 * val_dict[m.x]` Now `der_dict[m.x] = 2` (if `m.y=2`) and `der_dict[m.y] = m.x`. 4. `_diff_GeneralExpression(m.y, ...)` -> `der_dict[m.y.expr] += der_dict[m.y]` Since `m.y.expr = 2`, this is `der_dict[2] += der_dict[m.y]`. And here we get the `KeyError` because `2` was never visited in the forward pass. If `m.y.expr` is a constant, then `der_dict[2]` doesn't need to be updated because it won't affect any variable's derivative. So adding the `is_constant` check should fix this. Let's try applying the fix. <channel|><|tool_call>call:edit_file{filepath:<|"|>pyomo/core/expr/calculus/diff_with_pyomo.py<|"|>,new_string:<|"|>def _diff_GeneralExpression(node, val_dict, der_dict): \"\"\" Reverse automatic differentiation for named expressions. Parameters ---------- node: The named expression val_dict: ComponentMap der_dict: ComponentMap \"\"\" if not is_constant(node.expr): der_dict[node.expr] += der_dict[node] <|"|>,old_string:<|"|>def _diff_GeneralExpression(node, val_dict, der_dict): \"\"\" Reverse automatic differentiation for named expressions. Parameters ---------- node: The named expression val_dict: ComponentMap der_dict: ComponentMap \"\"\" der_dict[node.expr] += der_dict[node] <|"|>}<tool_call|><|tool_response>
Turn 10at 368 s205 tokens out16,694 prompt tokens
Now let's verify the fix with the reproduction script.
TOOL CALL · run_command
{
  "command": "python3 - <<'PY'\nimport pyomo.environ as pyo\nfrom pyomo.core.expr.calculus.derivatives import Modes, differentiate\n\nm = pyo.ConcreteModel()\n\nm.x = pyo.Var(initialize=0)\n\n@m.Expression()\ndef y(blk):\n    return 2\n\n@m.Expression()\ndef product(blk):\n    return blk.x * blk.y\n\ntry:\n    diff_expr = differentiate(\n                expr=m.product,\n                wrt=m.x,\n                mode=Modes.reverse_symbolic\n            )\n    print(\"Successfully differentiated!\")\n    diff_expr.pprint()\nexcept Exception as e:\n    import traceback\n    traceback.print_exc()\nPY\n"
}
Result of run_command 160 characters
{
  "status": "ok",
  "stdout": "Successfully differentiated!\ny : Size=1, Index=None\n    Key  : Expression\n    None :        2.0\n",
  "stderr": "",
  "exit_code": 0
}
Generated tokens 205 tokens · stopped: STOP
Now let's verify the fix with the reproduction script. <channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY' import pyomo.environ as pyo from pyomo.core.expr.calculus.derivatives import Modes, differentiate m = pyo.ConcreteModel() m.x = pyo.Var(initialize=0) @m.Expression() def y(blk): return 2 @m.Expression() def product(blk): return blk.x * blk.y try: diff_expr = differentiate( expr=m.product, wrt=m.x, mode=Modes.reverse_symbolic ) print("Successfully differentiated!") diff_expr.pprint() except Exception as e: import traceback traceback.print_exc() PY <|"|>}<tool_call|><|tool_response>
Turn 11at 440 s82 tokens out5,502 prompt tokens
The reproduction script now passes.

Now I should run the tests that might be related to this. I'll search for `differentiate` or `diff_with_pyomo` in the tests.
TOOL CALL · run_command
{
  "command": "grep -rn \"differentiate\" tests/ | grep \"test_*.py\" | head -n 20"
}
Result of run_command 101 characters
{
  "status": "ok",
  "stdout": "",
  "stderr": "grep: tests/: No such file or directory\n",
  "exit_code": 0
}
Generated tokens 82 tokens · stopped: STOP
The reproduction script now passes. Now I should run the tests that might be related to this. I'll search for `differentiate` or `diff_with_pyomo` in the tests. <channel|><|tool_call>call:run_command{command:<|"|>grep -rn "differentiate" tests/ | grep "test_*.py" | head -n 20<|"|>}<tool_call|><|tool_response>
Turn 12at 444 s63 tokens out5,633 prompt tokens
Ah, I forgot to check the layout. The layout says `tests/` (plural) in the provided context.
Wait, let me check `ls` just to be sure where the tests are.
TOOL CALL · run_command
{
  "command": "ls -d tests*"
}
Result of run_command 237 characters
{
  "status": "error",
  "error_type": "CommandError",
  "error_message": "ls: cannot access 'tests*': No such file or directory\n",
  "details": {
    "stdout": "",
    "stderr": "ls: cannot access 'tests*': No such file or directory\n",
    "exit_code": 2
  }
}
Generated tokens 63 tokens · stopped: STOP
Ah, I forgot to check the layout. The layout says `tests/` (plural) in the provided context. Wait, let me check `ls` just to be sure where the tests are. <channel|><|tool_call>call:run_command{command:<|"|>ls -d tests*<|"|>}<tool_call|><|tool_response>
Turn 13at 448 s57 tokens out5,783 prompt tokens
Wait, the workspace layout description said:
`tests/` (there it is!).
Ah, maybe it's `test/`?

Let me check the root directory.
TOOL CALL · run_command
{
  "command": "ls -F"
}
Result of run_command 222 characters
{
  "status": "ok",
  "stdout": "CHANGELOG.md\nCITATION.cff\nCONTRIBUTING.md\nLICENSE.md\nMANIFEST.in\nREADME.md\nRELEASE.md\nconftest.py\ndoc/\nexamples/\npyomo/\nscripts/\nsetup.cfg\nsetup.py\n",
  "stderr": "",
  "exit_code": 0
}
Generated tokens 57 tokens · stopped: STOP
Wait, the workspace layout description said: `tests/` (there it is!). Ah, maybe it's `test/`? Let me check the root directory. <channel|><|tool_call>call:run_command{command:<|"|>ls -F<|"|>}<tool_call|><|tool_response>
Turn 14at 457 s129 tokens out5,946 prompt tokens
I don't see a `tests/` or `test/` directory in the root.
Wait, why did the environment prompt say `Workspace Layout` and mention `tests/`?
Wait, I'm looking at the `ls -F` output, there's no `tests/` directory.
Let me check if it's inside `pyomo/` maybe?

No, usually tests are in a separate directory.
Let me check if they are in `pyomo/tests`.
TOOL CALL · run_command
{
  "command": "ls -F pyomo/"
}
Result of run_command 236 characters
{
  "status": "ok",
  "stdout": "__init__.py\ncommon/\ncontrib/\ncore/\ndae/\ndataportal/\nduality/\nenviron/\ngdp/\nkernel/\nmpec/\nneos/\nnetwork/\nopt/\npysp/\nrepn/\nscripting/\nsolvers/\nutil/\nversion/\n",
  "stderr": "",
  "exit_code": 0
}
Generated tokens 129 tokens · stopped: STOP
I don't see a `tests/` or `test/` directory in the root. Wait, why did the environment prompt say `Workspace Layout` and mention `tests/`? Wait, I'm looking at the `ls -F` output, there's no `tests/` directory. Let me check if it's inside `pyomo/` maybe? No, usually tests are in a separate directory. Let me check if they are in `pyomo/tests`. <channel|><|tool_call>call:run_command{command:<|"|>ls -F pyomo/<|"|>}<tool_call|><|tool_response>
Turn 15at 463 s105 tokens out6,180 prompt tokens
Still no tests.
Wait, `conftest.py` is in the root!
If `conftest.py` is in the root, then pytest should be able to find tests.
Maybe the tests are just not in a directory named `tests`?

Let me search for all `test_*.py` files in the workspace.
TOOL CALL · run_command
{
  "command": "find . -name \"test_*.py\" | head -n 20"
}
Result of run_command 973 characters
{
  "status": "ok",
  "stdout": "./examples/pyomobook/test_book_examples.py\n./examples/doc/samples/scripts/test_scripts.py\n./pyomo/core/tests/diet/test_diet.py\n./pyomo/core/tests/examples/test_kernel_examples.py\n./pyomo/core/tests/examples/test_pyomo.py\n./pyomo/core/tests/examples/test_amplbook2.py\n./pyomo/core/tests/examples/test_tutorials.py\n./pyomo/core/tests/unit/test_numeric_expr_zerofilter.py\n./pyomo/core/tests/unit/test_smap.py\n./pyomo/core/tests/unit/test_numeric_expr.py\n./pyomo/core/tests/unit/test_matrix_constraint.py\n./pyomo/core/tests/unit/test_template_expr.py\n./pyomo/core/tests/unit/test_enums.py\n./pyomo/core/tests/unit/test_dict_objects.py\n./pyomo/core/tests/unit/test_sos_v2.py\n./pyomo/core/tests/unit/test_var_set_bounds.py\n./pyomo/core/tests/unit/test_mutable.py\n./pyomo/core/tests/unit/test_visitor.py\n./pyomo/core/tests/unit/test_logical_expr_expanded.py\n./pyomo/core/tests/unit/test_preprocess.py\n",
  "stderr": "",
  "exit_code": 0
}
Generated tokens 105 tokens · stopped: STOP
Still no tests. Wait, `conftest.py` is in the root! If `conftest.py` is in the root, then pytest should be able to find tests. Maybe the tests are just not in a directory named `tests`? Let me search for all `test_*.py` files in the workspace. <channel|><|tool_call>call:run_command{command:<|"|>find . -name "test_*.py" | head -n 20<|"|>}<tool_call|><|tool_response>

Patch, tests and logs

Final code change Included
diff --git a/pyomo/core/expr/calculus/diff_with_pyomo.py b/pyomo/core/expr/calculus/diff_with_pyomo.py
index 952e8ec..b1d5716 100644
--- a/pyomo/core/expr/calculus/diff_with_pyomo.py
+++ b/pyomo/core/expr/calculus/diff_with_pyomo.py
@@ -328,7 +328,8 @@ def _diff_GeneralExpression(node, val_dict, der_dict):
     val_dict: ComponentMap
     der_dict: ComponentMap
     """
-    der_dict[node.expr] += der_dict[node]
+    if not is_constant(node.expr):
+        der_dict[node.expr] += der_dict[node]
 
 
 def _diff_ExternalFunctionExpression(node, val_dict, der_dict):
Test output Included
============================= test session starts ==============================
collected 29 items

pyomo/core/tests/unit/test_derivs.py ...........s................s       [100%]

==================================== PASSES ====================================
- generated xml file: /tmp/rebench-grade-b086352a04564c4a886797632c9a48cb.xml --
=========================== short test summary info ============================
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_NPV
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_abs
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_acos
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_asin
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_atan
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_constant_named_expressions
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_cos
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_div
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_duplicate_expressions
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_exp
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_expressiondata
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_linear_expression
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_log
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_log10
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_multiple_named_expressions
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_nested
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_nested_named_expressions
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_pow
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_prod
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_sin
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_sqrt
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_sum
PASSED pyomo/core/tests/unit/test_derivs.py::TestDerivs::test_tan
PASSED pyomo/core/tests/unit/test_derivs.py::TestDifferentiate::test_bad_mode
PASSED pyomo/core/tests/unit/test_derivs.py::TestDifferentiate::test_bad_wrt
PASSED pyomo/core/tests/unit/test_derivs.py::TestDifferentiate::test_reverse_numeric
PASSED pyomo/core/tests/unit/test_derivs.py::TestDifferentiate::test_reverse_symbolic
SKIPPED [1] pyomo/core/tests/unit/test_derivs.py:259: Could not find the amplgsl.dll library
SKIPPED [1] pyomo/core/tests/unit/test_derivs.py:327: test requires sympy
======================== 27 passed, 2 skipped in 0.55s =========================
Test errors Included
Test report (JUnit) Included
<?xml version="1.0" encoding="utf-8"?><testsuites name="pytest tests"><testsuite name="pytest" errors="0" failures="0" skipped="2" tests="29" time="0.555" timestamp="2026-11-14T05:03:33.677064+00:00" hostname="2a78e72cfde7"><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_NPV" time="0.001" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_abs" time="0.001" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_acos" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_asin" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_atan" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_constant_named_expressions" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_cos" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_div" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_duplicate_expressions" time="0.001" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_exp" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_expressiondata" time="0.001" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_external" time="0.010"><skipped type="pytest.skip" message="Could not find the amplgsl.dll library">/pyomo/pyomo/core/tests/unit/test_derivs.py:259: Could not find the amplgsl.dll library</skipped></testcase><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_linear_expression" time="0.001" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_log" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_log10" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_multiple_named_expressions" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_nested" time="0.001" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_nested_named_expressions" time="0.001" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_pow" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_prod" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_sin" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_sqrt" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_sum" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDerivs" name="test_tan" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDifferentiate" name="test_bad_mode" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDifferentiate" name="test_bad_wrt" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDifferentiate" name="test_reverse_numeric" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDifferentiate" name="test_reverse_symbolic" time="0.000" /><testcase classname="pyomo.core.tests.unit.test_derivs.TestDifferentiate" name="test_sympy" time="0.000"><skipped type="pytest.skip" message="test requires sympy">/pyomo/pyomo/core/tests/unit/test_derivs.py:327: test requires sympy</skipped></testcase></testsuite></testsuites>
Agent log Included
  [   0.0s] 📋 System Prompt: You are a principal Python software engineer resolving a repository issue in `/workspace`.
  [   0.0s] 🎯 Task Prompt: You are evaluating a software engineering task for repository Pyomo/pyomo.
  [  33.9s] 💭 (1268 chars) "The user is reporting a `KeyError` when using Pyomo's automatic differentiation 
(`differentiate`) with a constant `Expre..."
  [  33.9s] 🔧 run_command (27 lines) python3 - <<'PY'
  [  34.6s]   → error (exit 0): 
  [  45.4s] 💭 (206 chars) "The reproduction code fails because `pint` is not installed, and the code uses 
`units=pyo.units.mol`. I should remove th..."
  [  45.4s] 🔧 run_command (27 lines) python3 - <<'PY'
  [  45.5s]   🔧 
  [  60.5s] 💭 (567 chars) "The reproduction is successful. The error is indeed `KeyError: "Component with id '...': 
2.0"`.

Now let's examine the c..."
  [  60.5s] 📖 read_file (pyomo/core/expr/calculus/diff_with_pyomo.py)
  [  60.5s]   ✓ {'status': 'ok', 'filepath': 'pyomo/core/expr/calculus/diff_with_pyomo.py', 'content': 
'_unary_map[\'sqrt\'] = _diff_sqr…
  [  72.7s] 💭 (609 chars) "In `_diff_GeneralExpression`:
```python
def _diff_GeneralExpression(node, val_dict, der_dict):
    """
    Reverse autom..."
  [  72.7s] 📖 read_file (pyomo/common/collections/component_map.py)
  [  72.8s]   ✓ {'status': 'ok', 'filepath': 'pyomo/common/collections/component_map.py', 'content': '#  
_______________________________…
  [  99.4s] 💭 (1262 chars) "`ComponentMap` uses `id(obj)` as keys. This is intended to avoid hashing subclasses of 
`NumericValue`. However, if `obj`..."
  [  99.4s] 📖 read_file (pyomo/core/expr/calculus/diff_with_pyomo.py)
  [  99.5s]   ✓ {'status': 'ok', 'filepath': 'pyomo/core/expr/calculus/diff_with_pyomo.py', 'content': '            
self.operation_func …
  [ 109.9s] 💭 (363 chars) "In `_reverse_diff_helper`:
1. `_LeafToRootVisitor` is used to compute values and initialize `der_dict`.
2. `der_dict[exp..."
  [ 109.9s] 📖 read_file (pyomo/core/expr/calculus/diff_with_pyomo.py)
  [ 109.9s]   ✓ {'status': 'ok', 'filepath': 'pyomo/core/expr/calculus/diff_with_pyomo.py', 'content': '_diff_map = 
dict()\n_diff_map[_e…
  [ 183.9s] 💭 (4033 chars) "In `_LeafToRootVisitor.visit`:
```python
    def visit(self, node, values):
        self.val_dict[node] = self.operation..."
  [ 183.9s] 📖 read_file (pyomo/core/expr/calculus/diff_with_pyomo.py)
  [ 184.0s]   ✓ {'status': 'ok', 'filepath': 'pyomo/core/expr/calculus/diff_with_pyomo.py', 'content': '#  
_____________________________…
  [ 196.9s] 💭 (402 chars) "It imports `nonpyomo_leaf_types` from `pyomo.core.expr.visitor`. And it imports 
`is_constant` from `pyomo.core.expr.numv..."
  [ 196.9s] 🔧 run_command (5 lines) python3 - <<'PY'
  [ 197.0s]   → is_constant(2)=True
  [ 340.8s] 💭 (6608 chars) "So `is_constant` is perfect.

Let's modify `_diff_GeneralExpression` in `pyomo/core/expr/calculus/diff_with_pyomo.py` to..."
  [ 340.8s] ✏️ edit_file (pyomo/core/expr/calculus/diff_with_pyomo.py)
  [ 340.9s]   ✓ {'status': 'ok', 'filepath': 'pyomo/core/expr/calculus/diff_with_pyomo.py', 'occurrences': 1, 
'strategy': 'unescaped', '…
  [ 351.0s] 💭 (54 chars) "Now let's verify the fix with the reproduction script."
  [ 351.0s] 🔧 run_command (28 lines) python3 - <<'PY'
  [ 351.1s]   → Successfully differentiated!
  [ 422.9s] 💭 (161 chars) "The reproduction script now passes.

Now I should run the tests that might be related to this. I'll search for `differen..."
  [ 422.9s] 🔧 run_command grep -rn "differentiate" tests/ | grep "test_*.py" | head -n 20
  [ 422.9s]   🔧 
  [ 427.2s] 💭 (153 chars) "Ah, I forgot to check the layout. The layout says `tests/` (plural) in the provided context.
Wait, let me check `ls` jus..."
  [ 427.2s] 🔧 run_command ls -d tests*
  [ 427.2s]   → error (exit 0): 
  [ 431.2s] 💭 (127 chars) "Wait, the workspace layout description said:
`tests/` (there it is!).
Ah, maybe it's `test/`?

Let me check the root dir..."
  [ 431.2s] 🔧 run_command ls -F
  [ 431.2s]   → CHANGELOG.md
  [ 439.8s] 💭 (345 chars) "I don't see a `tests/` or `test/` directory in the root.
Wait, why did the environment prompt say `Workspace Layout` and..."
  [ 439.8s] 🔧 run_command ls -F pyomo/
  [ 439.9s]   → __init__.py
  [ 446.4s] 💭 (244 chars) "Still no tests.
Wait, `conftest.py` is in the root!
If `conftest.py` is in the root, then pytest should be able to find ..."
  [ 446.4s] 🔧 run_command find . -name "test_*.py" | head -n 20
  [ 446.5s]   → ./examples/pyomobook/test_book_examples.py
Native result row
{
  "agent_error": "Agent exceeded session timeout (7.5 min)",
  "duration_seconds": 471.69,
  "error": "Agent exceeded session timeout (7.5 min)",
  "grade": {
    "collected_tests": 29,
    "competition_junit_ok": true,
    "error": null,
    "required_issues_count": 0,
    "resolved": true,
    "status_counts": {
      "PASSED": 27,
      "SKIPPED": 2
    },
    "strict_clean_patch": true,
    "test_exit_code": 0
  },
  "instance_id": "pyomo__pyomo-3017",
  "pass_idx": 0,
  "patch_chars": 568,
  "phase1_seconds": 469.7,
  "repo": "Pyomo/pyomo",
  "request_log_path": "/kaggle-root/working/r31/rollouts_X/requests/pyomo__pyomo-3017__p0__r2.jsonl",
  "resolved": true,
  "rollout_idx": 2,
  "run_key": "pyomo__pyomo-3017__p0__r2",
  "strict_clean_patch": true,
  "tool_calls": 15,
  "total_llm_calls": 15,
  "trace_path": "/kaggle-root/working/r31/rollouts_X/traces/trace_pyomo__pyomo-3017__p0__r2.json"
}