# \[Closed\] \[PATCH 0/1\]Add #adjugate method to matrix class

**URL:** <https://www.ruby-forum.com/t/closed-patch-0-1-add-adjugate-method-to-matrix-class/232803>\
**Category:** Development\
**Created:** [October 29, 2014, 3:54am UTC](https://www.ruby-forum.com/t/closed-patch-0-1-add-adjugate-method-to-matrix-class/232803 "2014-10-29T03:54:44Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [October 29, 2014, 3:54am UTC](https://www.ruby-forum.com/t/closed-patch-0-1-add-adjugate-method-to-matrix-class/232803/1 "2014-10-29T03:54:44Z")

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Issue #10056 has been updated by Marc-Andre L…

Category set to lib  
Status changed from Assigned to Closed

Committed, thanks for this request!

* * *

Feature #10056: [PATCH 0/1]Add #adjugate method to matrix class

> **[Feature #10056: \[PATCH 0/1\]Add #adjugate method to matrix class - Ruby master...](https://bugs.ruby-lang.org/issues/10056#change-49706)**
>
> Redmine

- Author: gogo tanaka
- Status: Closed
- Priority: Normal
- Assignee: Marc-Andre L.
- Category: lib
- Target version:

* * *

Add Matrix#adjugate to make a matrix adjugate.

Adjugate is really important operator to handle matrix (especially  
Exploring Data with ruby)

```auto
# Property

* Any n-th matrix `m`(object of Matrix class) Satisfy the following 
conditions

Matrix.identity(n) == (m.adjugate * m) / m.det

# Differential vector or matrix
Let A = (a(i, j)) is n-th matrix, A(i, j) is adjugate matrix excluding 
the j and column i row A.

def. ∂det(A)/∂a(i,j) = (-1) ** (i + j) * det(A(i, j))

```

Some people regards adjugate matrix as Hermitian adjoint.

I regard adjuate matrix as transpose of the cofactor matrix by  
referencing [Adjugate matrix - Wikipedia](http://en.wikipedia.org/wiki/Adjugate_matrix).

—Files--------------------------------  
add\_matrix#adjugate\_method.patch (2.22 KB)  
update\_news.patch (867 Bytes)  
implement.patch (1.07 KB)  
add\_test.patch (1.84 KB)