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changeset 13872:779e15b69738

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hilb.m: 10% speedup by using in-place accumulation. * hilb.m: 10% speedup by using in-place accumulation.
author Rik <octave@nomad.inbox5.com>
date Wed, 16 Nov 2011 20:49:04 -0800
parents adf60d6dc1dd
children 1bf8c244040a
files scripts/special-matrix/hilb.m
diffstat 1 files changed, 14 insertions(+), 16 deletions(-) [+]
line wrap: on
line diff
--- a/scripts/special-matrix/hilb.m	Wed Nov 16 16:17:13 2011 -0500
+++ b/scripts/special-matrix/hilb.m	Wed Nov 16 20:49:04 2011 -0800
@@ -54,28 +54,26 @@
 
 function retval = hilb (n)
 
-
   if (nargin != 1)
     print_usage ();
+  elseif (! isscalar (n))
+    error ("hilb: N must be a scalar integer");
   endif
 
-  nmax = length (n);
-  if (nmax == 1)
-    retval = zeros (n);
-    tmp = 1:n;
-    for i = 1:n
-      retval (i, :) = 1.0 ./ (tmp + (i - 1));
-    endfor
-  else
-    error ("hilb: expecting scalar argument, found something else");
-  endif
+  retval = zeros (n);
+  tmp = 1:n;
+  for i = 1:n
+    retval(i, :) = 1.0 ./ tmp;
+    tmp++;
+  endfor
 
 endfunction
 
-%!assert((hilb (2) == [1, 1/2; 1/2, 1/3]
-%! && hilb (3) == [1, 1/2, 1/3; 1/2, 1/3, 1/4; 1/3, 1/4, 1/5]));
+
+%!assert (hilb (2), [1, 1/2; 1/2, 1/3])
+%!assert (hilb (3), [1, 1/2, 1/3; 1/2, 1/3, 1/4; 1/3, 1/4, 1/5])
 
-%!error hilb ();
+%!error hilb ()
+%!error hilb (1, 2)
+%!error <N must be a scalar integer> hilb (ones(2))
 
-%!error hilb (1, 2);
-