# HG changeset patch
# User Rik <octave@nomad.inbox5.com>
# Date 1307466251 25200
# Node ID 6835bc816ef2034aa92e0e70dfdd8ec91a08a531
# Parent  65b7ce254ba3057c1dff0f550b27e8cf783d3fa4
shiftdim.m: Use common idiom for finding first non-singleton dimension.
Add tests for function.

* shiftdim.m: Use common idiom for finding first non-singleton dimension.
Add functional tests to .m file.

diff -r 65b7ce254ba3 -r 6835bc816ef2 scripts/general/shiftdim.m
--- a/scripts/general/shiftdim.m	Thu Jun 02 16:31:13 2011 +0200
+++ b/scripts/general/shiftdim.m	Tue Jun 07 10:04:11 2011 -0700
@@ -57,14 +57,9 @@
   orig_dims = size (x);
 
   if (nargin == 1)
-    ## Find the first singleton dimension.
-    n = 0;
-    while (n < nd && orig_dims(n+1) == 1)
-      n++;
-    endwhile
-  endif
-
-  if (! isscalar (n) || floor (n) != n)
+    ## Find the first non-singleton dimension.
+    (n = find (orig_dims != 1, 1) - 1) || (n = nd);
+  elseif (! (isscalar (n) && n == fix (n)))
     error ("shiftdim: N must be a scalar integer");
   endif
 
@@ -78,7 +73,7 @@
   elseif (n > 0)
     ## We need permute here instead of reshape to shift values in a
     ## compatible way.
-    y = permute (x, [n+1:ndims(x) 1:n]);
+    y = permute (x, [n+1:nd 1:n]);
   else
     y = x;
   endif
@@ -86,3 +81,20 @@
   ns = n;
 
 endfunction
+
+
+%!test
+%! x = rand (1, 1, 4, 2);
+%! [y, ns] = shiftdim (x);
+%! assert (size (y), [4 2]);
+%! assert (ns, 2);
+%! assert (shiftdim (y, -2), x);
+%! assert (size (shiftdim (x, 2)), [4 2]);
+%!assert (size (shiftdim (rand (0, 1, 2))), [0 1 2]);
+
+%% Test input validation
+%!error(shiftdim ());
+%!error(shiftdim (1,2,3));
+%!error(shiftdim (1, ones (2)));
+%!error(shiftdim (1, 1.5));
+