# HG changeset patch
# User Jaroslav Hajek <highegg@gmail.com>
# Date 1236975973 -3600
# Node ID f464119ec1656585320380c73de2656170ebd143
# Parent  22a7e46907427f0df5f23917414b129e96ebf025
further simplify some stats funcs

diff -r 22a7e4690742 -r f464119ec165 scripts/ChangeLog
--- a/scripts/ChangeLog	Fri Mar 13 20:52:33 2009 +0100
+++ b/scripts/ChangeLog	Fri Mar 13 21:26:13 2009 +0100
@@ -2,6 +2,10 @@
 
 	* statistics/base/mean.m: Simplify.
 	* statistics/base/meansq.m: Optimize.
+	* statistics/base/center.m: Fix behvaior with vectors, simplify.
+	* statistics/base/std.m: Simplify using `center'.
+	* statistics/base/var.m: Ditto.
+	* statistics/base/cov.m: Ditto.
 
 2009-03-13  Jaroslav Hajek  <highegg@gmail.com>
 
diff -r 22a7e4690742 -r f464119ec165 scripts/statistics/base/center.m
--- a/scripts/statistics/base/center.m	Fri Mar 13 20:52:33 2009 +0100
+++ b/scripts/statistics/base/center.m	Fri Mar 13 21:26:13 2009 +0100
@@ -29,30 +29,34 @@
 ## Author: KH <Kurt.Hornik@wu-wien.ac.at>
 ## Description: Center by subtracting means
 
-function retval = center (x, varargin)
+function retval = center (x, dim)
 
   if (nargin != 1 && nargin != 2)
     print_usage ();
   endif
 
-  if (isvector (x))
-    retval = x - mean (x, varargin{:});
-  elseif (ismatrix (x))
-    if nargin < 2
-      dim = find (size (x) > 1, 1);
-      if (isempty (dim))
-	dim = 1; 
-      endif;
+  if (nargin < 2)
+    t = find (size (x) != 1);
+    if (isempty (t))
+      dim = 1;
     else
-      dim = varargin{1};
+      dim = t(1);
     endif
-    sz = ones (1, ndims (x));
-    sz (dim) = size (x, dim);
-    retval = x - repmat (mean (x, dim), sz);
-  elseif (isempty (x))
+  endif
+  n = size (x, dim);
+
+  if (n == 1)
+    retval = zeros (size (x));
+  elseif (n > 0)
+    if (isvector (x))
+      retval = x - sum (x) / n;
+    else
+      mx = sum (x, dim) / n;
+      idx(1:ndims (x)) = {':'}; 
+      idx{dim} = ones (1, n);
+      retval = x - mx(idx{:});
+    endif
+  else
     retval = x;
-  else
-    error ("center: x must be a vector or a matrix");
   endif
-
 endfunction
diff -r 22a7e4690742 -r f464119ec165 scripts/statistics/base/cov.m
--- a/scripts/statistics/base/cov.m	Fri Mar 13 20:52:33 2009 +0100
+++ b/scripts/statistics/base/cov.m	Fri Mar 13 21:26:13 2009 +0100
@@ -57,11 +57,11 @@
     if (rows (y) != n)
       error ("cov: x and y must have the same number of observations");
     endif
-    x = x - ones (n, 1) * sum (x) / n;
-    y = y - ones (n, 1) * sum (y) / n;
+    x = center (x, 1);
+    y = center (y, 1);
     c = conj (x' * y / (n - 1));
   elseif (nargin == 1)
-    x = x - ones (n, 1) * sum (x) / n;
+    x = center (x, 1);
     c = conj (x' * x / (n - 1));
   endif
 
diff -r 22a7e4690742 -r f464119ec165 scripts/statistics/base/std.m
--- a/scripts/statistics/base/std.m	Fri Mar 13 20:52:33 2009 +0100
+++ b/scripts/statistics/base/std.m	Fri Mar 13 21:26:13 2009 +0100
@@ -76,19 +76,13 @@
     opt = 0;
   endif
 
-  sz = size(a);
-  if (sz (dim) == 1)
-    retval = zeros(sz);
+  n = size (a, dim);
+  if (n == 1)
+    retval = zeros (sz);
   elseif (numel (a) > 0)
-    rng = ones (1, length (sz));
-    rng (dim) = sz (dim);
-    if (opt == 0)
-      retval = sqrt (sumsq (a - repmat(mean (a, dim), rng), dim) / (sz(dim) - 1));
-    else
-      retval = sqrt (sumsq (a - repmat(mean (a, dim), rng), dim) / sz(dim));
-    endif
+    retval = sqrt (sumsq (center (a, dim), dim) / (n + opt - 1));
   else
-    error ("std: invalid matrix argument");
+    error ("std: x must not be empty");
   endif
 
 endfunction
diff -r 22a7e4690742 -r f464119ec165 scripts/statistics/base/var.m
--- a/scripts/statistics/base/var.m	Fri Mar 13 20:52:33 2009 +0100
+++ b/scripts/statistics/base/var.m	Fri Mar 13 21:26:13 2009 +0100
@@ -56,19 +56,13 @@
     opt = 0;
   endif
 
-  sz = size (x);
-  if (prod (sz) < 1)
-    error ("var: x must not be empty");
-  elseif (sz(dim) == 1)
-    y = 0;
+  n = size (a, dim);
+  if (n == 1)
+    retval = zeros (sz);
+  elseif (numel (a) > 0)
+    retval = sumsq (center (a, dim), dim) / (n + opt - 1);
   else
-    rng = ones (1, length (sz));
-    rng (dim) = sz (dim);
-    if (opt == 0)
-      y = sumsq (x - repmat(mean (x, dim), rng), dim) / (sz(dim) - 1);
-    else
-      y = sumsq (x - repmat(mean (x, dim), rng), dim) / sz(dim);
-    endif
+    error ("var: x must not be empty");
   endif
 
 endfunction