diff options
| author | knu <knu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2007-03-20 02:29:09 +0000 |
|---|---|---|
| committer | knu <knu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2007-03-20 02:29:09 +0000 |
| commit | fd08f3ac6b8fe61e6d4931d693d3c67fe7e00215 (patch) | |
| tree | c7c22e6fb1eec6c67ee00fafdd8452e61ee0dbe6 /lib | |
| parent | d4fb0b1f6d23529805bbad16896a8792da6aac39 (diff) | |
* lib/matrix.rb (Matrix::inverse_from): adding partial pivoting to
the Gauss-Jordan algorithm, making it stable. a patch from
Peter Vanbroekhoven. [ruby-core:10641]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@12105 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/matrix.rb | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/lib/matrix.rb b/lib/matrix.rb index c62acdf9aa..470db19b05 100644 --- a/lib/matrix.rb +++ b/lib/matrix.rb @@ -590,15 +590,21 @@ class Matrix a = src.to_a for k in 0..size - if (akk = a[k][k]) == 0 - i = k - begin - Matrix.Raise ErrNotRegular if (i += 1) > size - end while a[i][k] == 0 + i = k + akk = a[k][k].abs + for j in (k+1)..size + v = a[j][k].abs + if v > akk + i = j + akk = v + end + end + Matrix.Raise ErrNotRegular if akk == 0 + if i != k a[i], a[k] = a[k], a[i] @rows[i], @rows[k] = @rows[k], @rows[i] - akk = a[k][k] end + akk = a[k][k] for i in 0 .. size next if i == k |