stan-dev / stan-dev/math

Rewrite LDLT code

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#418 2 comments 0 reactions 0 assignees View on GitHub

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code cleanup
Dominant language
C++
Stars
839
Forks
220
Avg merge
2d 4h
Merged PRs (30d)
14

Description

Summary:

The LDLT code is non-idiomatic relative to the Stan code-base. It constructs an object that isn't valid and it's on the caller to verify that it's correct. This leads to more difficult testing and maintenance than necessary.

Description:

I'm finding it very difficult to test behavior of this function. We should rewrite it.

Additional Information:

The code is pretty fast. Whatever we do, we don't want to give up the speed.

Current Version:

v2.12.0

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 locating the LDLT implementation and the callers that currently verify its result; the issue names no files or tests. Read how the current object is constructed and tested, then define a rewrite that produces a valid object, is easier to test, and preserves the reported speed.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
backend
Issue type
Refactor
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
20/100

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