pymc-devs / pymc-devs/pytensor

Should IncSubtensor ignore duplicates by default, like numpy?

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indexing NumPy compatibility request discussion
Dominant language
Python
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208
Avg merge
2d 14h
Merged PRs (30d)
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Description

Description
import pytensor.tensor as pt
import numpy as np

x = np.zeros(3)
x[[0, 0, 0]] += 1
print(x)
# [1, 0, 0]

x = pt.zeros(3)
x = x[[0, 0, 0]].inc(1)
print(x.eval())
# [3, 0, 0]

x = pt.zeros(3)
x = x[[0, 0, 0]].inc(1, ignore_duplicates=True)
print(x.eval())
# [1, 0, 0]

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the NumPy and PyTensor examples in the issue, then inspect the IncSubtensor entry point and its handling of ignore_duplicates. Done means deciding and documenting the default duplicate behavior, with regression coverage showing the expected result for repeated indices.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
backend
Issue type
Feature
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
48/100

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