Changeset 12289 for issm/trunk-jpl/src/c/objects/Kriging/GaussianVariogram.cpp

Timestamp:

05/25/12 15:23:23 (13 years ago)

Author:

Mathieu Morlighem

Message:

Added Covariance for Kriging calculation (similar to gslib)

File:

• issm/trunk-jpl/src/c/objects/Kriging/GaussianVariogram.cpp (modified) (2 diffs)

issm/trunk-jpl/src/c/objects/Kriging/GaussianVariogram.cpp

@@ -59 +59 @@
 
 /*Variogram function*/
+/*FUNCTION GaussianVariogram::Covariance{{{1*/
+double GaussianVariogram::Covariance(double deltax,double deltay){
+        /*The covariance can be deduced from the variogram from the following
+         * relationship:
+         *    2 gamma = C(x,x) + C(y,y) -2 C(x,y)
+         * so
+         *    C(h) = sill - gamma                                            */
+        double h2,a,cova;
+
+        /*Calculate length square*/
+        h2=pow(deltax,2.)+pow(deltay,2.);
+
+        /*return covariance*/
+        a     = 1./3.;
+        cova = (sill-nugget)*exp(-h2/(a*range*range));
+
+        //if(h2<0.0000001) cova = sill;
+
+        return cova;
+}
+/*}}}*/
 /*FUNCTION GaussianVariogram::SemiVariogram{{{1*/
 double GaussianVariogram::SemiVariogram(double deltax,double deltay){
@@ -70 +91 @@
         a     = 1./3.;
         gamma = (sill-nugget)*(1.-exp(-h2/(a*range*range))) + nugget;
+
+        //if(h2>1000*1000) printf("gamma = %g h= %g\n",gamma,sqrt(h2));
+        printf("h = %g gamma = %g\n",sqrt(h2),gamma);
         return gamma;
 }