Enabled population-based FSSH-3, as well as a different initializtion of the current-based FSSH-3

Author: alexvakimov

src/dyn/dyn_hop_proposal_fssh3.cpp

@@ -152,7 +152,12 @@ vector<double> hopping_probabilities_fssh3(dyn_control_params& prms, CMATRIX& de
   //====== Testing options =========
 
   int size_option = 0; // not used here, = prms.fssh3_size_option; // 0 - N elements, only populations; 1 - N^2 elements - also coherences
-  int approach_option = 1; //  = prms.fssh3_approach_option; // 0 - master equation (J contains hopping probabilities); 1 - kinetic approach (J contains fluxes)
+  int approach_option = prms.fssh3_approach_option; 
+  // 0 - master equation (J contains hopping probabilities); 
+  // 1 - kinetic approach (J contains fluxes), initialize J to be all zeroes
+  // 2 - kinetic approach (J contains fluxes), initialize J to J_{i,i+1} = 1.0 and J_{i-1,i} = -1.0, and 0.0 otherwise
+
+
   int decomp_option = 0; // not used here, = prms.fssh3_decomp_option; // in this version, it selects the 
 
   //=========================== Step 1: definition of vectorized densities ==================================

src/opt/grad_descent.cpp

@@ -249,11 +249,20 @@ MATRIX run_opt(MATRIX& x, MATRIX& y, double dt, double nsteps, double err_tol, i
     int n = x.n_rows;
     MATRIX A(n,n);  A = 0.0;
     if(approach_option==0){  A.identity(); }
-    else if(approach_option==1 or approach_option==2){
+    else if(approach_option==1){
       for(i=0;i<n;i++){
         for(j=0;j<n;j++){  A.set(i,j, 0.0 ); }
       }
     }
+    else if(approach_option==2){
+      for(i=0;i<n;i++){
+        for(j=0;j<n;j++){  
+          if(j-i==1){  A.set(i,j, 1.0); }
+          else if(j-i==-1){ A.set(i,j, -1.0); }
+          else{         A.set(i,j, 0.0 );  }
+        }
+      }
+    }
 
     double Lag, L0, L1, L2, L3;
     double L = 1.0;