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diff scripts/statistics/base/std.m @ 12656:6b2f14af2360

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Overhaul functions in statistics/base directory. Widen input validation to accept logicals. Return correct class of output, e.g., 'single' depending on class of input. Correct or add tests for above. * center.m, cov.m, kendall.m, mean.m, meansq.m, median.m, mode.m, prctile.m, quantile.m, ranks.m, run_count.m, runlength.m, spearman.m, statistics.m, std.m, var.m, logistic_inv.m: Overhaul as described above * corrcoef.m: Overhaul + remove input validation already done by cov(). * cor.m, logit.m, ppplot.m, table.m: Only align test blocks. * gls.m, ols.m: Only correct class of output, no logical inputs for regression. * histc.m: Only change spacing of code to be uniform. * iqr.m: Overhaul + 2X speedup by calling empirical_inv just once. * kurtosis.m: Overhaul + replace repmat instances with center(). * mahalanobis.m: Overhaul + use bsxfun for centering data. * moment.m: Overhaul + replace repmat instances with center(). * probit.m, range.m: Redo input validation and add tests. * skewness.m: Overhaul + replace repmat instances with center(). * zscore.m: Overhaul + replace repmat instances with center() + use bsxfun.
author Rik <octave@nomad.inbox5.com>
date Sat, 07 May 2011 14:52:08 -0700
parents c792872f8942
children 645a87434fcb
line wrap: on
line diff
--- a/scripts/statistics/base/std.m
+++ b/scripts/statistics/base/std.m
@@ -67,7 +67,7 @@
     print_usage ();
   endif
 
-  if (! (isnumeric (x)))
+  if (! (isnumeric (x) || islogical (x)))
     error ("std: X must be a numeric vector or matrix");
   endif
 
@@ -78,18 +78,25 @@
     error ("std: normalization OPT must be 0 or 1");
   endif
 
+  nd = ndims (x);
   sz = size (x);
   if (nargin < 3)
     ## Find the first non-singleton dimension.
-    dim = find (sz > 1, 1);
-    if (isempty (dim))
-      dim = 1;
+    (dim = find (sz > 1, 1)) || (dim = 1);
+  else
+    if (!(isscalar (dim) && dim == fix (dim))
+        || !(1 <= dim && dim <= nd))
+      error ("std: DIM must be an integer and a valid dimension");
     endif
   endif
 
-  n = size (x, dim);
+  n = sz(dim);
   if (n == 1)
-    retval = zeros (sz);
+    if (isa (x, 'single'))
+      retval = zeros (sz, 'single');
+    else
+      retval = zeros (sz);
+    endif
   elseif (numel (x) > 0)
     retval = sqrt (sumsq (center (x, dim), dim) / (n - 1 + opt));
   else
@@ -102,14 +109,20 @@
 %!test
 %! x = ones (10, 2);
 %! y = [1, 3];
-%! assert(std (x) == [0, 0] && abs (std (y) - sqrt (2)) < sqrt (eps));
-%! assert (std (x, 0, 3), zeros (10, 2))
-%! assert (std (ones (3, 1, 2), 0, 2), zeros (3, 1, 2))
+%! assert(std (x) == [0, 0]);
+%! assert(std (y), sqrt (2), sqrt (eps));
+%! assert(std (x, 0, 2), zeros (10, 1));
+
+%!assert(std (ones (3, 1, 2), 0, 2), zeros (3, 1, 2));
+%!assert(std ([1 2], 0), sqrt(2)/2, 5*eps);
+%!assert(std ([1 2], 1), 0.5, 5*eps);
+%!assert(std(1), 0);
+%!assert(std(single(1)), single(0));
 
 %% Test input validation
 %!error std ();
 %!error std (1, 2, 3, 4);
-%!error std (true(1,2))
+%!error std (['A'; 'B'])
 %!error std (1, -1);
 %!error std ([], 1);