source: issm/oecreview/Archive/16554-17801/ISSM-17341-17342.diff@ 17802

../trunk-jpl/src/c/classes/kriging/Observations.cpp

@@ -379 +379 @@
         IssmPDouble* A = xNew<IssmPDouble>((n_obs+1)*(n_obs+1));
         IssmPDouble* B = xNew<IssmPDouble>(n_obs+1);
 
+        IssmDouble unbias = variogram->Covariance(0.,0.);
         /*First: Create semivariogram matrix for observations*/
         for(i=0;i<n_obs;i++){
                 for(j=0;j<=i;j++){
                         A[i*(n_obs+1)+j] = variogram->Covariance(x[i]-x[j],y[i]-y[j]);
                         A[j*(n_obs+1)+i] = A[i*(n_obs+1)+j];
                 }
-                A[i*(n_obs+1)+n_obs] = 1.;
+                A[i*(n_obs+1)+n_obs] = unbias;
+                //A[i*(n_obs+1)+n_obs] = 1.;
         }
-        for(i=0;i<n_obs;i++) A[n_obs*(n_obs+1)+i]=1.;
+        for(i=0;i<n_obs;i++) A[n_obs*(n_obs+1)+i]=unbias;
+        //for(i=0;i<n_obs;i++) A[n_obs*(n_obs+1)+i]=1.;
         A[n_obs*(n_obs+1)+n_obs] = 0.;
 
         /*Get semivariogram vector associated to this location*/
         for(i=0;i<n_obs;i++) B[i] = variogram->Covariance(x[i]-x_interp,y[i]-y_interp);
-        B[n_obs] = 1.;
+        B[n_obs] = unbias;
+        //B[n_obs] = 1.;
 
         /*Solve the three linear systems*/
 #if _HAVE_GSL_