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require_relative '../../spec_helper'
require_relative 'fixtures/classes'
require 'matrix'
describe "Matrix.diagonal" do
before :each do
@m = Matrix.diagonal(10, 11, 12, 13, 14)
end
it "returns an object of type Matrix" do
@m.should be_kind_of(Matrix)
end
it "returns a square Matrix of the right size" do
@m.column_size.should == 5
@m.row_size.should == 5
end
it "sets the diagonal to the arguments" do
(0..4).each do |i|
@m[i, i].should == i + 10
end
end
it "fills all non-diagonal cells with 0" do
(0..4).each do |i|
(0..4).each do |j|
if i != j
@m[i, j].should == 0
end
end
end
end
describe "for a subclass of Matrix" do
it "returns an instance of that subclass" do
MatrixSub.diagonal(1).should be_an_instance_of(MatrixSub)
end
end
end
describe "Matrix.diagonal?" do
it "returns true for a diagonal Matrix" do
Matrix.diagonal([1, 2, 3]).diagonal?.should be_true
end
it "returns true for a zero square Matrix" do
Matrix.zero(3).diagonal?.should be_true
end
it "returns false for a non diagonal square Matrix" do
Matrix[[0, 1], [0, 0]].diagonal?.should be_false
Matrix[[1, 2, 3], [1, 2, 3], [1, 2, 3]].diagonal?.should be_false
end
it "returns true for an empty 0x0 matrix" do
Matrix.empty(0,0).diagonal?.should be_true
end
it "raises an error for rectangular matrices" do
[
Matrix[[0], [0]],
Matrix[[0, 0]],
Matrix.empty(0, 2),
Matrix.empty(2, 0),
].each do |rectangular_matrix|
-> {
rectangular_matrix.diagonal?
}.should raise_error(Matrix::ErrDimensionMismatch)
end
end
end
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