Implement dst1.sci in Scilab

1 files changed, 55 insertions, 21 deletions

diff --git a/macros/dst1.sci b/macros/dst1.sci
index 7f2165f..c2f84ed 100644
--- a/macros/dst1.sci
+++ b/macros/dst1.sci
@@ -1,28 +1,62 @@
-function y = dst1(x, varargin)
+function y = dst1(x, n)
 //Computes the type I discrete sine transform of x
-//Calling Sequence
+//Calling Sequence:
 //y= dst1(x)
 //y= dst1(x,n)
-//Parameters 
+//Parameters: 
 //x: real or complex valued vector
 //n= Length to which x is trimmed before transform 
-//Description
-//This is an Octave function.
-//Computes the type I discrete sine transform of x. If n is given, then x is padded or trimmed to length n before computing the transform. If x is a matrix, compute the transform along the columns of the the matrix.
-funcprot(0);
-
-lhs= argn(1);
-rhs= argn(2);
-
-if(rhs>2)
-error("Wrong number of input arguments");
-end
-
-select(rhs)
-	case 1 then
-		y = callOctave("dst", x);
-	case 2 then
-		y = callOctave("dst", x, varargin(1));
-end
+//Description:
+//Computes the type 1 discrete sine transform of x. If n is given, then x is padded or trimmed to length n before computing the transform. 
+//If x is a matrix, compute the transform along the columns of the the matrix.
+//Example:
+//dst1([1 3 6])
+//ans = [7.94974, -5, 1.94974]
+
+  funcprot(0);
+  rhs = argn(2);
+  if (rhs < 1 | rhs > 2)
+    error("ds1: wrong number of input arguments");
+  end
+
+  transpose = (size(x, 'r') == 1);
+  if (transpose)
+    x = x (:);
+  end
+
+  [nr, nc] = size(x);
+  if (rhs == 1)
+    n = nr;
+  elseif (n > nr)
+    x = [ x ; zeros(n-nr, nc) ];
+  elseif (n < nr)
+    x (nr-n+1 : n, :) = [];
+  end
+
+  d = [ zeros(1, nc); x; zeros(1, nc); -flipdim(x, 1) ];
+  y = fft(d, -1, find(size(d) ~= 1, 1))/2*%i;
+  y = y(2:nr+1, :);
+  if (isreal(x))
+    y = real (y);
+  end
+
+  if (transpose)
+    y = y.';
+  end
+
 endfunction
 
+//input validation:
+//assert_checkerror("dst1()", "ds1: wrong number of input arguments");
+//assert_checkerror("dst1(1, 2, 3)", "Wrong number of input arguments.");
+
+//tests:
+//x = log(linspace(0.1,1,32));
+//y = dst1(x);
+//assert_checkalmostequal(y(3), sum(x.*sin(3*%pi*[1:32]/33)), 100*%eps);
+//
+//assert_checkalmostequal(dst1([-1; -3; -6]), [-7.9497; 5.0000; -1.9497], 5*10^-5);
+//assert_checkalmostequal(dst1([-1 2 2], 5), [3.2321, 0.8660, -3.0000], 5*10^-5);
+//assert_checkalmostequal(dst1([1+2*%i, 5+3*%i, 8+2*%i]), [11.3639+5.8284*%i, -7.0000-0*%i, 1.3640-0.1716*%i], 5*10^-4);
+//assert_checkalmostequal(dst1([1+2*%i; 5+3*%i; 8+2*%i], 2), [7.7942+3.4641*%i; -6.0622-0*%i; 0], 5*10^-5);
+//assert_checkalmostequal(dst1([-1-3*%i, 4*%i; -2-7*%i, 3]), [-2.5981-8.6603*%i, 2.5981+3.4641*%i; 0.8660+3.4641*%i, -2.5981+3.4641*%i], 5*10^-5);