josdejong/mathjs

Matrix sum along a dimension is defined to return a `MathScalarType`, but might return higher dimension

Open

#3,202 opened on May 12, 2024

View on GitHub
 (5 comments) (0 reactions) (1 assignee)JavaScript (1,298 forks)batch import
bughelp wantedtypescript

Repository metrics

Stars
 (13,832 stars)
PR merge metrics
 (No merged PRs in 30d)

Description

Describe the bug When summing over an axis of a matrix, we always lose just one dimension. If the matrix is 2D, we'll get a 1D array. If the matrix is 3D, we'll get a 2D matrix. What happens now, is that math.sum declares that it returns a MathScalarType, instead of optionally returning a matrix.

To Reproduce

const mat = math.matrix([[1,2,3],[4,5,6]])
console.log(math.sum(mat, 0))

> DenseMatrix { _data: [ 5, 7, 9 ], _size: [ 3 ], _datatype: undefined }

Contributor guide

Research direction
Locate the type definition for `math.sum` and inspect how the return type is determined. The issue is that the return type should be a matrix when summing along a dimension, not always a scalar. Examine the function signature and the logic that handles axis summation to understand where the type declaration is incorrect.
Tech stack
javascript
Domain
api
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JavaScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65