finished (?) chapter, add example code

programmingstyle/code/calculate_sines.m

@@ -0,0 +1,30 @@
+function sines = calculate_sines(x, amplitudes, frequencies)
+  % Function calculates sinewaves with all combinations of 
+  % given amplitudes and frequencies.
+  % Arguments:   x, a vector of radiants for which the sine should be
+  %              computed
+  %              amplitudes, a vector of amplitudes
+  %              frequencies, a vector of frequencies
+  %
+  % Returns:     a 3-D Matrix of sinewaves, 2nd dimension represents
+  %              the amplitudes, 3rd the frequencies.
+  
+  sines = zeros(length(x), length(amplitudes), length(frequencies));
+
+  for i = 1:length(amplitudes)
+    sines(:, i, :) = sines_with_frequencies(x, amplitudes(i), frequencies); 
+  end
+end
+
+
+function sines = sines_with_frequencies(x, amplitude, frequencies)
+  sines = zeros(length(x), length(frequencies));
+  for i = 1:length(frequencies)
+    sines(:,i) = sinewave(x, amplitude, frequencies(i));
+  end
+end
+
+
+function sine = sinewave(x, amplitude, frequency)
+    sine = sin(2 .* pi .* x *frequency) .* amplitude; 
+end