* lib/matrix.rb: Add Matrix#laplace_expansion.

  patch by gogo tanaka [#10073]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47835 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 18 insertions, 0 deletions

diff --git a/test/matrix/test_matrix.rb b/test/matrix/test_matrix.rb
index eb62a326b6..2d99cead42 100644
--- a/test/matrix/test_matrix.rb
+++ b/test/matrix/test_matrix.rb
@@ -293,6 +293,24 @@ class TestMatrix < Test::Unit::TestCase
     assert_raise(ExceptionForMatrix::ErrDimensionMismatch) { Matrix[[2,0,1],[0,-2,2]].cofactor(0, 0) }
   end
 
+  def test_laplace_expansion
+    assert_equal(1, Matrix[[1]].laplace_expansion(row: 0))
+    assert_equal(45, Matrix[[7,6], [3,9]].laplace_expansion(row: 1))
+    assert_equal(0, Matrix[[0,0],[0,0]].laplace_expansion(column: 0))
+    assert_equal(-7, Matrix[[0,0,1],[0,7,6],[1,3,9]].laplace_expansion(column: 2))
+
+    assert_equal(Vector[3, -2], Matrix[[Vector[1, 0], Vector[0, 1]], [2, 3]].laplace_expansion(row: 0))
+
+    assert_raise(ExceptionForMatrix::ErrDimensionMismatch) { @m1.laplace_expansion(row: 1) }
+    assert_raise(ArgumentError) { Matrix[[7,6], [3,9]].laplace_expansion() }
+    assert_raise(ArgumentError) { Matrix[[7,6], [3,9]].laplace_expansion(foo: 1) }
+    assert_raise(ArgumentError) { Matrix[[7,6], [3,9]].laplace_expansion(row: 1, column: 1) }
+    assert_raise(ArgumentError) { Matrix[[7,6], [3,9]].laplace_expansion(row: 2) }
+    assert_raise(ArgumentError) { Matrix[[0,0,1],[0,7,6],[1,3,9]].laplace_expansion(column: -1) }
+
+    assert_raise(RuntimeError) { Matrix.empty(0, 0).laplace_expansion(row: 0) }
+  end
+
   def test_regular?
     assert(Matrix[[1, 0], [0, 1]].regular?)
     assert(Matrix[[1, 0, 0], [0, 1, 0], [0, 0, 1]].regular?)