Forum: Ruby-dev [Assigned] [PATCH 0/1]Add #adjugate method to matrix class

Eabad423977cfc6873b8f5df62b848a6?d=identicon&s=25 unknown (Guest)
on 2014-07-18 03:29
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Issue #10056 has been updated by Hiroshi SHIBATA.

Status changed from Open to Assigned
Assignee set to Marc-Andre Lafortune

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

* Author: gogo tanaka
* Status: Assigned
* Priority: Normal
* Assignee: Marc-Andre Lafortune
* Category:
* Target version:
Add Matrix#adjugate to make a matrix adjugate.

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

# Property

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

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

add_matrix#adjugate_method.patch (2.22 KB)
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