Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / signal-1.1.3 / wkeep.m

diff --git a/octave_packages/signal-1.1.3/wkeep.m b/octave_packages/signal-1.1.3/wkeep.m
new file mode 100644 (file)
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+++ b/octave_packages/signal-1.1.3/wkeep.m
@@ -0,0 +1,65 @@
+## Copyright (C) 2008 Sylvain Pelissier <sylvain.pelissier@gmail.com>
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{y}] =} wkeep(@var{x,l,opt})
+## Extract the elements of x of size l from the center, the right or the left.
+## @end deftypefn
+
+function y = wkeep(x,l,opt = 'c')
+
+  if (nargin < 2|| nargin > 3); print_usage; end
+  if(isvector(x))
+
+    if(l > length(x))
+      error('l must be or equal the size of x');
+    end
+
+    if(opt=='c')
+      s = (length(x)-l)./2;
+      y = x(1+floor(s):end-ceil(s));
+
+    elseif(opt=='l')
+      y=x(1:l);
+
+    elseif(opt=='r')
+      y = x(end-l+1:end);
+
+    else
+      error('opt must be equal to c, l or r');
+    end
+  else
+    if(length(l) == 2)
+      s1 = (length(x)-l(1))./2;
+      s2 = (length(x)-l(2))./2;
+    else
+      error('For a matrix l must be a 1x2 vector');
+    end
+
+    if(nargin==2)
+      y = x(1+floor(s1):end-ceil(s1),1+floor(s2):end-ceil(s2));
+    else
+      if(length(opt) == 2)
+        firstr=opt(1);
+        firstc=opt(2);
+      else
+        error('For a matrix l must be a 1x2 vector');
+      end
+
+      y=x(firstr:firstr+l(1)-1,firstc:firstc+l(2)-1);
+    end
+
+  end
+end