From 3b51e3a11fd39daafaaaf54bcbf81814d48c3942 Mon Sep 17 00:00:00 2001
From: stomar <stomar@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Thu, 11 Jan 2018 19:36:30 +0000
Subject: matrix.rb: add Matrix#antisymmetric?

* lib/matrix.rb: add Matrix#antisymmetric?.
  Proposed by Yilo (@yiloo). Patch by Marcus Stollsteimer (@stomar).
  [Fix GH-1788]
* spec/ruby/library/matrix/antisymmetric_spec.rb: add specs.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61775 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 lib/matrix.rb | 12 ++++++++++++
 1 file changed, 12 insertions(+)

(limited to 'lib/matrix.rb')

diff --git a/lib/matrix.rb b/lib/matrix.rb
index 923e716b35..4a61976b0e 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -801,6 +801,18 @@ class Matrix
     true
   end
 
+  #
+  # Returns +true+ if this is an antisymmetric matrix.
+  # Raises an error if matrix is not square.
+  #
+  def antisymmetric?
+    Matrix.Raise ErrDimensionMismatch unless square?
+    each_with_index(:upper) do |e, row, col|
+      return false unless e == -rows[col][row]
+    end
+    true
+  end
+
   #
   # Returns +true+ if this is a unitary matrix
   # Raises an error if matrix is not square.
-- 
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