pymc-devs / pymc-devs/pytensor

Rethink the special-case for Elemwise/Blockwise InplaceOptimizer for "large graphs"

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

Description

Description

As brought up in #1494 it's odd to have a hard-coded 500 number at which we stop trying to inplace scalar graphs. We could consider:

  1. Remove this behavior and address underlying performance issues (if we can reproduce)
  2. Make it a config variable
  3. Make it more cleaver, not just scalar, but perhaps variable.size if that's statically known as well

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 locating the Elemwise/Blockwise InplaceOptimizer implementation and reviewing issue #1494 to understand the hard-coded 500 threshold and the reported large-graph behavior. Reproduce the performance concern if possible, then define and validate one of the proposed policies with tests or benchmarks showing the new behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
performance
Issue type
Refactor
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
30/100

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