code changes by Shashikiran Yadalam during FOSSEE Fellowship 2018

1 files changed, 63 insertions, 28 deletions

diff --git a/macros/downsample.sci b/macros/downsample.sci
index 9bd1591..e0bc508 100644
--- a/macros/downsample.sci
+++ b/macros/downsample.sci
@@ -1,31 +1,66 @@
+// 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
+// Author:[insert name]
+// Organization: FOSSEE, IIT Bombay
+// Email: toolbox@scilab.in
+
+
+//Function File vary = downsample (x, n)
+//Function File y = downsample (x, n, offset)
+// Downsample the signal, selecting every nth element.  If x
+// is a matrix, downsample every column.
+//
+// If offset is defined, select every nth element starting at
+// sample offset.
+//
+//
+
+//Test cases:
+
+//1.downsample([1,2,3,4,5],2)
+//EXPECTED OUTPUT:[1,3,5]
+
+
+//2.downsample([1;2;3;4;5],2)
+//EXPECTED OUTPUT:[1;3;5]
+
+
+//3.downsample([1,2;3,4;5,6;7,8;9,10],2)
+//EXPECTED OUTPUT:[1,2;5,6;9,10]
+
+
+//4.downsample([1,2,3,4,5],2,1)
+//EXPECTED OUTPUT:[2,4]
+
+
+//5.downsample([1,2;3,4;5,6;7,8;9,10],2,1)
+//EXPECTED OUTPUT:[3,4;7,8]
+
+
+
 function y = downsample (x, n, phase)
-//This function downsamples the signal by selecting every nth element.
-//Calling Sequence
-//y = downsample (x, n)
-//y = downsample (x, n, phase)
-//Parameters 
-//x: scalar, vector or matrix of real or complex numbers
-//n: real number or vector
-//phase: integer value, 0 <= phase <= (n - 1), default value 0, or logical
-//Description
-//This is an Octave function.
-//This function downsamples the signal by selecting every nth element supplied as parameter 2. If x is a matrix, the function downsamples every column.
-//If the phase is specified, every nth element is selected starting from the sample phase. The default phase is 0.
-//Examples
-//downsample([1,2,4],2)
-//ans  =
-//    1.    4.  
-
-funcprot(0);
-rhs = argn(2)
-if(rhs<2 | rhs>3)
-error("Wrong number of input arguments.")
+[nargout,nargin]=argn();
+  if (nargin<2 | nargin>3)
+       error ("wrong no. of input arguments");
+       end
+
+if nargin==2
+    phase=0;
+    else
+  if phase > n-1
+    warning("This is incompatible with Matlab (phase = 0:n-1). See octave-forge signal package release notes for details." )
+  end
 end
-  
-	select(rhs)
-	case 2 then
-	y = callOctave("downsample",x,n)
-	case 3 then
-	y = callOctave("downsample",x,n,phase)
-	end
+
+  if isvector(x)
+    y = x(phase + 1:n:$);
+  else
+    y = x(phase + 1:n:$,:);
+  end
+
 endfunction