pymc-devs / pymc-devs/pytensor

Arange with constant outputs does not result into a type with constant shape

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enhancement feature request shape inference
Dominant language
Python
Stars
644
Forks
208
Avg merge
2d 14h
Merged PRs (30d)
16

Description

Describe the issue:

pt.arange allocates a vector of length that depends on input values but the output shape has dynamic type

Reproducable code example:
assert pt.arange(10).type.shape == (10, )
Error message:
(None, ) != (10,)
PyTensor version information:

'2.16.1'

Context for the issue:

used here https://github.com/pymc-labs/pymc-marketing/blob/main/pymc_marketing/mmm/transformers.py#L102C50-L102C59

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Research direction

Reproduce the assertion with pt.arange(10) and inspect the pt.arange entry point, along with its use in pymc_marketing/mmm/transformers.py at the referenced line. Determine how constant input values affect the reported shape; done means the example reports (10,) instead of (None,).

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
backend
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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