1 files changed, 49 insertions, 24 deletions
diff --git a/macros/dctmtx.sci b/macros/dctmtx.sci
index e0c2354..e399d47 100644
--- a/macros/dctmtx.sci
+++ b/macros/dctmtx.sci
@@ -1,25 +1,50 @@
-function [y]= dctmtx(n)
-
-// Performs Direct Cosine Transformation
-// Calling Sequence
-//	[y]=dctmtx(n)
-// Parameters
-//	n: Real scalar integer greater than or equal to 1
-// Description
-//	This is an Octave function
-//	dctmtx(n) returns a Discrete cosine transform matrix of order n-by-n. It is useful for jpeg image compression. D*A is the DCT of the columns of A and D'*A is the inverse DCT of the columns of A (when A is n-by-n).
-// Examples
-// 1.	dctmtx(2)
-//	ans = [0.70711   0.70711;   0.70711  -0.70711]
-// 2.	dctmtx(3)
-//	ans = [5.7735e-01   5.7735e-01   5.7735e-01;
-//	       7.0711e-01   4.9996e-17  -7.0711e-01;
-//	       4.0825e-01  -8.1650e-01   4.0825e-01]
-
-funcprot(0);
-rhs=argn(2);
-if (rhs<1) then
-	error ("Wrong number of input arguments.")
-else [y]=callOctave("dctmtx",n)
-end
+// Copyright (C) 2018 - IIT Bombay - FOSSEE
+//
+// This file must be used under the terms of the CeCILL.
+// This source file is licensed as described in the file COPYING, which
+// you should have received as part of this distribution.  The terms
+// are also available at
+// http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
+// Original Source : https://octave.sourceforge.io/signal/
+// Modifieded by:Sonu Sharma, RGIT Mumbai
+// Organization: FOSSEE, IIT Bombay
+// Email: toolbox@scilab.in
+
+function T = dctmtx(n)
+    // Return the DCT transformation matrix of size N-by-N.
+
+    //Calling Sequence
+    //T = dctmtx(n)
+
+    //Parameters
+    //n: Real scalar integer greater than or equal to 1
+
+    //Description
+    //dctmtx(n) returns a Discrete cosine transform matrix (D) of order n-by-n. It is useful for jpeg image compression. D*A is the DCT of the columns of A and D'*A is the inverse DCT of the columns of A (when A is n-by-n).
+
+    // Examples
+    //n= 3;
+    //T = dctmtx(n)
+    //Output:
+    // T  =
+    //
+    //    0.5773503    0.5773503    0.5773503
+    //    0.7071068    5.000D-17  - 0.7071068
+    //    0.4082483  - 0.8164966    0.4082483
+
+
+    funcprot();
+    [nargout nargin] = argn();
+    if nargin ~= 1
+        error("dctmtx: invalid number of inputs")
+    end
+
+    if n > 1
+        T = [ sqrt(1/n)*ones(1,n) ; ...
+        sqrt(2/n)*cos((%pi/2/n)*([1:n-1]'*[1:2:2*n])) ];
+    elseif n == 1
+        T = 1;
+    else
+        error ("dctmtx: n must be at least 1");
+    end
 endfunction