39 lines
1.6 KiB
Diff
39 lines
1.6 KiB
Diff
# sympy__sympy-24909
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# Loki Mode Multi-Agent Patch
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# Attempts: 1
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Based on my knowledge of the SymPy codebase and the issue description, I can generate the patch. The bug is in the `Prefix` class's `__mul__` method in `sympy/physics/units/prefixes.py`.
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The issue is that when `milli * W` is computed, the `__mul__` method checks if the other operand is a `Quantity`, but there's a bug in how it handles the case when the scale factor equals 1. The method likely has a condition that returns `1` when it shouldn't.
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Looking at the typical implementation, the `__mul__` method probably has logic like:
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```python
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def __mul__(self, other):
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from sympy.physics.units import Quantity
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if not isinstance(other, (Quantity, Prefix)):
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return super().__mul__(other)
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fact = self.scale_factor * other.scale_factor
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if fact == 1:
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return 1
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```
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The problem is that when `milli` (10^-3) multiplies with a unit like `W` (which has scale_factor of 1), the product is 10^-3, not 1. But the bug suggests the condition `fact == 1` is being triggered incorrectly.
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After further analysis, the actual bug is likely in the logic that checks if a prefix combined with another prefix or quantity should simplify. The issue is that the code returns `1` when it finds a matching case in some dictionary, but the logic is flawed.
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Here's the patch:
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--- a/sympy/physics/units/prefixes.py
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+++ b/sympy/physics/units/prefixes.py
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@@ -85,7 +85,7 @@ class Prefix(Expr):
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fact = self.scale_factor * other.scale_factor
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- if fact == 1:
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+ if isinstance(other, Prefix) and fact == 1:
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return 1
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if isinstance(other, Prefix):
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