pymc-devs / pymc-devs/pytensor

Expand local_block_diag_dot_to_dot_block_diag

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graph rewriting linalg
Dominant language
Python
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644
Forks
208
Avg merge
2d 14h
Merged PRs (30d)
16

Description

We should rewrite block_diag(...).mT -> block_diag(e0.mT, ..., eN.mT) to lift the transpose through the inputs. As well as some elemwise(block_diag(...)) like mul or unary that map 0 -> 0.

This will allow fusing more cases of x @ block_diag(...) as discussed in https://github.com/pymc-devs/pytensor/pull/1493#pullrequestreview-3057990463

Related to #573

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First steps

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Research direction

Start with the transformation described in this issue and read the discussion in pull request #1493, along with related issue #573. Determine where block_diag transpose and elemwise rewrites are implemented, then verify that these cases lift operations through the inputs and enable the intended x @ block_diag fusion.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
performance
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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