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* lib/matrix.rb: Add Matrix#adjucate

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patch by gogo tanaka [#10056]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48182 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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marcandre 2014-10-29 02:43:28 +00:00
parent dc38c87779
commit 764524f65b
4 changed files with 36 additions and 0 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
Wed Oct 29 11:43:11 2014 Marc-Andre Lafortune <ruby-core@marc-andre.ca>
* lib/matrix.rb: Add Matrix#adjucate
patch by gogo tanaka [#10056]
Wed Oct 29 11:42:33 2014 Marc-Andre Lafortune <ruby-core@marc-andre.ca>
* lib/matrix.rb: Add aliases for Vector#cross & dot

1
NEWS
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@ -148,6 +148,7 @@ with all sufficient information, see the ChangeLog file.
by deleting the specified row and column.
* Matrix#cofactor(row, column) returns the (row, column) cofactor
which is obtained by multiplying the first minor by (-1)**(row + column).
* Matrix#adjugate returns the adjugate of the matrix.
* hstack and vstack are new instance and class methods to stack matrices
horizontally and vertically.
* Matrix#laplace_expansion(row_or_column: num) returns the laplace_expansion

15
lib/matrix.rb
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@ -62,6 +62,7 @@ end
# * #minor(*param)
# * #first_minor(row, column)
# * #cofactor(row, column)
# * #adjugate
# * #laplace_expansion(row_or_column: num)
# * #cofactor_expansion(row_or_column: num)
#
@ -689,6 +690,20 @@ class Matrix
det_of_minor * (-1) ** (row + column)
end
#
# Returns the adjugate of the matrix.
#
# Matrix[ [7,6],[3,9] ].adjugate
# => 9 -6
# -3 7
#
def adjugate
Matrix.Raise ErrDimensionMismatch unless square?
Matrix.build(row_count, column_count) do |row, column|
cofactor(column, row)
end
end
#
# Returns the Laplace expansion along given row or column.
#

15
test/matrix/test_matrix.rb
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@ -14,6 +14,9 @@ class TestMatrix < Test::Unit::TestCase
@c1 = Matrix[[Complex(1,2), Complex(0,1), 0], [1, 2, 3]]
@e1 = Matrix.empty(2,0)
@e2 = Matrix.empty(0,3)
@a3 = Matrix[[4, 1, -3], [0, 3, 7], [11, -4, 2]]
@a5 = Matrix[[2, 0, 9, 3, 9], [8, 7, 0, 1, 9], [7, 5, 6, 6, 5], [0, 7, 8, 3, 0], [7, 8, 2, 3, 1]]
@b3 = Matrix[[-7, 7, -10], [9, -3, -2], [-1, 3, 9]]
end
def test_matrix
@ -302,6 +305,18 @@ class TestMatrix < Test::Unit::TestCase
assert_raise(ExceptionForMatrix::ErrDimensionMismatch) { Matrix[[2,0,1],[0,-2,2]].cofactor(0, 0) }
end
def test_adjugate
assert_equal(Matrix.empty, Matrix.empty.adjugate)
assert_equal(Matrix[[1]], Matrix[[5]].adjugate)
assert_equal(Matrix[[9,-6],[-3,7]], Matrix[[7,6],[3,9]].adjugate)
assert_equal(Matrix[[45,3,-7],[6,-1,0],[-7,0,0]], Matrix[[0,0,1],[0,7,6],[1,3,9]].adjugate)
assert_equal(Matrix.identity(5), (@a5.adjugate * @a5) / @a5.det)
assert_equal(Matrix.I(3), Matrix.I(3).adjugate)
assert_equal((@a3 * @b3).adjugate, @b3.adjugate * @a3.adjugate)
assert_equal(4**(@a3.row_count-1) * @a3.adjugate, (4 * @a3).adjugate)
assert_raise(ExceptionForMatrix::ErrDimensionMismatch) { @m1.adjugate }
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))