Macaulay2 / Macaulay2/M2

MutableMatrix multiplication bug

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#4,376 3 comments 0 reactions 0 assignees View on GitHub

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Engine
Dominant language
Macaulay2
Stars
435
Forks
297
Avg merge
4d 20h
Merged PRs (30d)
11

Description

```
i1 : R=frac(QQ[x])[y]

o1 = R

o1 : PolynomialRing

i2 : a=mutableMatrix{{x}}

o2 = | x |

o2 : MutableMatrix

i3 : b=mutableMatrix{{y}}

o3 = | y |

o3 : MutableMatrix

i4 : a*b

o4 = | 1127510310816062349084802013071819938...3887237698090958848/0x2 |

o4 : MutableMatrix

```
(I had to abbreviate the output because it was over 65k characters...)

Contributor guide

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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 transcript with R=frac(QQ[x])[y] and the 1x1 MutableMatrix values x and y, then trace the MutableMatrix multiplication entry point. Compare the result with the expected product and add a regression test that prevents the oversized incorrect output.

Written by the indexing model from the issue text.

Assessment

Domain
backend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
45/100

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