Implement synthesis.sci in Scilab

1 files changed, 66 insertions, 24 deletions

diff --git a/macros/synthesis.sci b/macros/synthesis.sci
index 7224686..ede8601 100644
--- a/macros/synthesis.sci
+++ b/macros/synthesis.sci
@@ -1,25 +1,67 @@
-function x= synthesis(Y,C)
-//Compute a signal from its short-time Fourier transform
-//Calling Sequence
-//X= synthesis(Y,C)
-//Parameters 
-//Y: Shirt-time fourier transform
-//C: 3-element vector C specifying window size, increment, window type.
-//Description
-//Compute a signal from its short-time Fourier transform Y and a 3-element vector C specifying window size, increment, and window type.
-//The values Y and C can be derived by
-//[Y, C] = stft (X , ...)
-funcprot(0);
-lhs= argn(1);
-rhs= argn(2);
-
-if(rhs<2 | rhs >2)
-	error("Wrong number of input arguments");
-end
-
-select(rhs)
-	case 2 then
-            x= callOctave("synthesis", Y,C);
-
-end
+function x = synthesis (y, c)
+//Compute a signal from its short-time Fourier transform.
+//Calling Sequence:
+//synthesis(y, c)
+//Parameters:
+//y: Real or complex matrix representing a signal's short-time fourier transform.
+//c: 3-element vector C specifying window size, increment and window type.
+//Description:
+//Compute a signal from its short-time Fourier transform 'y' and a 3-element vector 'c' specifying window size, increment, and window type.
+//A window type of 1 represents a hanning window, 2 represents a hamming window and 3 represents a rectangular window.
+//The values 'y' and 'c' can be derived by [y, c] = stft (x, ...)
+
+  funcprot(0);
+  rhs = argn(2);
+  if (rhs ~= 2)
+    error("synthesis: wrong number of input arguments");
+  end
+
+  if (length(c) ~= 3)
+    error ("synthesis: C must contain exactly 3 elements");
+  end
+
+  w_size = c(1);
+  inc    = c(2);
+  w_type = c(3);
+
+  if (w_type == 1)
+    w_coeff = window('hn', w_size);
+  elseif (w_type == 2)
+    w_coeff = window('hm', w_size);
+  elseif (w_type == 3)
+    w_coeff = ones (w_size, 1);
+  else
+    error ("synthesis: window_type must be 1, 2, or 3");
+  end
+
+  if (isnan(w_coeff))
+    w_coeff = 1;
+  end
+  z = real(fft(y, 1, find(size(y) ~= 1, 1)));
+  st = fix((w_size-inc) / 2);
+  z = z(st+1:st+inc, :);
+  w_coeff = w_coeff(st+1:st+inc);
+
+  nc = size(z, 'c');
+  for i = 1:nc
+    z(:, i) = z(:, i) ./ w_coeff;
+  end
+
+  x = matrix(z, inc * nc, 1);
+
 endfunction
+
+//input validation:
+//assert_checkerror("synthesis(1)", "synthesis: wrong number of input arguments");
+//assert_checkerror("synthesis(1, [1 2])", "synthesis: C must contain exactly 3 elements");
+//assert_checkerror("synthesis(1, [1 2 3 4])", "synthesis: C must contain exactly 3 elements");
+//assert_checkerror("synthesis(1, [1 2 4])", "synthesis: window_type must be 1, 2, or 3");
+
+//tests:
+//assert_checkequal(synthesis(1, [1 1 1]), 1);
+//assert_checkequal(synthesis(4, [2 1 3]), 4);
+//assert_checkalmostequal(synthesis(-6, [2 1 2]), -75, %eps);
+//assert_checkalmostequal(synthesis(-9, [2; 1; 2]), -112.50, 10*%eps);
+//assert_checkequal(synthesis(5*%i, [2; 1; 3]), 0);
+//assert_checkequal(synthesis([1 2; -3, -6], [1; 1; 2]), [-1; -2]);
+//assert_checkalmostequal(synthesis([1 1+2*%i; -3-4*%i, -5], [2; 1; 2]), [-12.5; -25], %eps);