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Bug #7582

closed

a mistake in Matrix#lup RDoc

Added by pypypy567 (py _) over 9 years ago. Updated over 9 years ago.

Status:
Closed
Priority:
Normal
Assignee:
-
Target version:
-
ruby -v:
ruby 2.0.0dev (2012-11-01) [i386-mswin32_100]
Backport:
[ruby-core:50946]

Description

http://bugs.ruby-lang.org/projects/ruby-trunk/repository/revisions/38300/entry/lib/matrix.rb#L1203

l * u == a * p # => true

http://bugs.ruby-lang.org/projects/ruby-trunk/repository/revisions/38300/entry/lib/matrix/lup_decomposition.rb#L7

and a m-by-m permutation matrix P so that LU = PA.

irb(main):001:0> require 'matrix'
=> true
irb(main):002:0> a = Matrix1, 2], [3, 4
=> Matrix1, 2], [3, 4
irb(main):003:0> l, u, p = a.lup
=> #<Matrix::LUPDecomposition:0xf813a8 @lu=3, 4], [(1/3), (2/3), @row_size=2, @col_size=2, @pivots=[1, 0], @pivot_sign=-1>
irb(main):004:0> l * u == a * p
=> false
irb(main):005:0> l * u == p * a
=> true


Files

matrix.rb.lup.patch (438 Bytes) matrix.rb.lup.patch pypypy567 (py _), 12/18/2012 01:15 AM
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