1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67
|
require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/classes', __FILE__)
require 'matrix'
describe "Matrix#**" do
describe "given an integer _n_" do
it "multiples the Matrix by itself _n_ times" do
m = Matrix[ [7,6], [3,9] ]
(m ** 1).should == m
(m ** 2).should == Matrix[ [67, 96], [48,99] ]
(m ** 2).should == m * m
(m ** 3).should == m * m * m
(m ** 4).should == m * m * m * m
(m ** 5).should == m * m * m * m * m
end
it "raises a ErrDimensionMismatch for non square matrices" do
m = Matrix[ [1, 1], [1, 2], [2, 3]]
lambda { m ** 3 }.should raise_error(Matrix::ErrDimensionMismatch)
lambda { m ** 0 }.should raise_error(Matrix::ErrDimensionMismatch)
end
describe "that is <= 0" do
it "returns the inverse of **(-n)" do
m = Matrix[ [1, 1], [1, 2] ]
(m ** -2).should == Matrix[ [5, -3], [-3, 2]]
(m ** -4).should == (m.inverse ** 4)
end
it "raises a ErrDimensionMismatch for irregular matrices" do
m = Matrix[ [1, 1], [1, 1] ]
lambda { m ** -2 }.should raise_error(Matrix::ErrNotRegular)
lambda { m ** 0 }.should raise_error(Matrix::ErrNotRegular)
end
end
end
ruby_version_is "" ... "1.9.1" do
it "raises a ErrOperationNotDefined exception for powers that aren't Integers" do
lambda {Matrix[ [1,2], [8,2] ] ** 2.5}.should \
raise_error(Matrix::ErrOperationNotDefined)
end
end
ruby_version_is "1.9.1" ... "1.9.3" do
it "raises a ErrOperationNotImplemented exception for powers that aren't Integers" do
lambda {Matrix[ [1,2], [8,2] ] ** 2.5}.should \
raise_error(Matrix::ErrOperationNotImplemented)
end
end
ruby_version_is "1.9.3" do
it "returns the power for non integer powers" do
a = Matrix[[5, 4], [4, 5]]
((a ** 0.5) ** 2).round(8).should == a
a = Matrix[[7, 10], [15, 22]]
((a ** 0.25) ** 4).round(8).should == a
end
end
describe "for a subclass of Matrix" do
it "returns an instance of that subclass" do
(MatrixSub.ins ** 1).should be_an_instance_of(MatrixSub)
end
end
end
|