@@ -12,5 +12,14 @@ module DSP def stddev Math.sqrt(variance) end + def cmux(r) + smaller, larger = self.size < r.size ? [self, r.dup] : [r.dup, self] + pad_amount = (larger.size - smaller.size) / 2 + pad_amount.times do + smaller.unshift nil + smaller << nil + end + larger.zip(smaller) + end end end lib/dsp/signal.rb @@ -14,4 +14,36 @@ class TestSignal < Test::Unit::TestCase assert_in_delta 3.16227766016838, DSP::Signal.new([1, 2, 3, 4, 5]).stddev, 0.001 end end + + context "cmuxing" do + setup do + @left = DSP::Signal.new([1, 2, 3, 4, 5]) + @right = DSP::Signal.new([2, 3, 4]) + end + + should "not modify the signals" do + @left.cmux(@right) + assert_equal [2, 3, 4], @right + end + + should "mux signals of the same size" do + assert_equal [[2, 2], [3, 3], [4, 4]], @right.cmux(@right) + end + + should "mux a smaller signal" do + assert_equal [[1, nil], [2, 2], [3, 3], [4, 4], [5, nil]], @left.cmux(@right) + end + + should "mux a larger signal" do + assert_equal [[1, nil], [2, 2], [3, 3], [4, 4], [5, nil]], @right.cmux(@left) + end + + should "mux a smaller signal with odd size" do + assert_equal [[2, 1], [3, 2], [4, nil]], @right.cmux([1, 2]) + end + + should "mux a larger signal with odd size" do + assert_equal [[1, 2], [2, 3], [3, 4], [4, nil]], @right.cmux([1, 2, 3, 4]) + end + end end test/test_signal.rb 42ae2e328c0559e507335a108293783631799a92 Scott Barron scott@elitists.net http://github.com/rubyist/dsp/commit/0857a0ed5245cef8d314a60ab62cf79d2e600883 0857a0ed5245cef8d314a60ab62cf79d2e600883 2009-01-22T10:06:03-08:00 2009-01-22T10:06:03-08:00 add Signal#cmux 47d4757a61e61b5e7b4a455b959d01ad34929fac Scott Barron scott@elitists.net