added functions which computes variances , the float complex functions seems to have a weak precision ( 1-e04 instead of 1-e06 for some value )

1 files changed, 39 insertions, 0 deletions

diff --git a/src/statisticsFunctions/variance/dvariancea.c b/src/statisticsFunctions/variance/dvariancea.c
new file mode 100644
index 00000000..2454968e
--- /dev/null
+++ b/src/statisticsFunctions/variance/dvariancea.c
@@ -0,0 +1,39 @@
+/*
+ *  Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
+ *  Copyright (C) 2008-2008 - INRIA - Allan SIMON
+ *
+ *  This file must be used under the terms of the CeCILL.
+ *  This source file is licensed as described in the file COPYING, which
+ *  you should have received as part of this distribution.  The terms
+ *  are also available at
+ *  http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
+ *
+ */
+
+#include "variance.h" 
+
+double	dvariancea(double *in, int size)
+{
+    int i = 0 ;
+    
+    double temp = 0 ;
+    double sumc = 0 ;
+    double variance = 0;
+    
+    double mean =  dmeana ( in , size );
+ 
+    for ( i = 0 ; i < size ; i++)
+    { 
+
+       temp += dpows (  (in[i]  - mean ) ,2 ) ;
+       sumc += (in[i]  - mean);     
+    }
+    
+    if ( fabs ( sumc) > 1e-16)
+        variance =  ( temp - dpows( sumc,2)/size)/ ( size -1);
+    else 
+        variance = ( temp )/ ( size -1);    
+    
+    return variance ;
+}
+