3 files changed, 17 insertions, 6 deletions

diff --git a/src/main.c b/src/main.c
index 92c53b9..8a63117 100644
--- a/src/main.c
+++ b/src/main.c
@@ -24,6 +24,7 @@ typedef struct nstrophy_parameters {
   double L;
   unsigned int print_freq;
   int seed;
+  unsigned int starting_time;
 } nstrophy_parameters;
 
 // usage message
@@ -119,10 +120,10 @@ int main (
 
   // run command
   if (command==COMMAND_UK){
-    uk(parameters.K1, parameters.K2, parameters.N1, parameters.N2, parameters.nsteps, parameters.nu, parameters.delta, parameters.L, u0, g, parameters.print_freq, nthreads, savefile);
+    uk(parameters.K1, parameters.K2, parameters.N1, parameters.N2, parameters.nsteps, parameters.nu, parameters.delta, parameters.L, u0, g, parameters.print_freq, parameters.starting_time, nthreads, savefile);
   }
   else if(command==COMMAND_EEA){
-    eea(parameters.K1, parameters.K2, parameters.N1, parameters.N2, parameters.nsteps, parameters.nu, parameters.delta, parameters.L, u0, g, parameters.print_freq, nthreads, savefile);
+    eea(parameters.K1, parameters.K2, parameters.N1, parameters.N2, parameters.nsteps, parameters.nu, parameters.delta, parameters.L, u0, g, parameters.print_freq, parameters.starting_time, nthreads, savefile);
   }
   else if(command==COMMAND_QUIET){
     quiet(parameters.K1, parameters.K2, parameters.N1, parameters.N2, parameters.nsteps, parameters.nu, parameters.delta, parameters.L, u0, g, nthreads, savefile);
@@ -345,6 +346,7 @@ int read_params(
   parameters->L=2*M_PI;
   parameters->nsteps=10000000;
   parameters->print_freq=1000;
+  parameters->starting_time=0;
   parameters->seed=17;
 
   if (param_str!=NULL){
@@ -516,6 +518,13 @@ int set_parameter(
       return(-1);
     }
   }
+  else if (strcmp(lhs,"starting_time")==0){
+    ret=sscanf(rhs,"%u",&(parameters->starting_time));
+    if(ret!=1){
+      fprintf(stderr, "error: parameter 'starting_time' should be an unsigned integer\n       got '%s'\n",rhs);
+      return(-1);
+    }
+  }
   else{
     fprintf(stderr, "error: unrecognized parameter '%s'\n",lhs);
     return(-1);
diff --git a/src/navier-stokes.c b/src/navier-stokes.c
index 12cba85..1ab4a44 100644
--- a/src/navier-stokes.c
+++ b/src/navier-stokes.c
@@ -16,6 +16,7 @@ int uk(
   _Complex double* u0,
   _Complex double* g,
   unsigned int print_freq,
+  unsigned int starting_time,
   unsigned int nthreads,
   FILE* savefile
 ){
@@ -46,7 +47,7 @@ int uk(
   }
 
   // iterate
-  for(t=0;t<nsteps;t++){
+  for(t=starting_time;t<starting_time+nsteps;t++){
     ins_step(u, K1, K2, N1, N2, nu, delta, L, g, fft1, fft2, ifft, tmp1, tmp2, tmp3);
     
     if(t%print_freq==0){
@@ -87,6 +88,7 @@ int eea(
   _Complex double* u0,
   _Complex double* g,
   unsigned int print_freq,
+  unsigned int starting_time,
   unsigned int nthreads,
   FILE* savefile
 ){
@@ -112,7 +114,7 @@ int eea(
   avg_en=0;
 
   // iterate
-  for(t=0;t<nsteps;t++){
+  for(t=starting_time;t<starting_time+nsteps;t++){
     ins_step(u, K1, K2, N1, N2, nu, delta, L, g, fft1, fft2, ifft, tmp1, tmp2, tmp3);
 
     energy=compute_energy(u, K1, K2);
diff --git a/src/navier-stokes.h b/src/navier-stokes.h
index 92ff754..57399a4 100644
--- a/src/navier-stokes.h
+++ b/src/navier-stokes.h
@@ -13,10 +13,10 @@ typedef struct fft_vects {
 } fft_vect;
 
 // compute u_k
-int uk( int K1, int K2, int N1, int N2, unsigned int nsteps, double nu, double delta, double L, _Complex double* u0, _Complex double* g, unsigned int print_freq, unsigned int nthreadsl, FILE* savefile);
+int uk( int K1, int K2, int N1, int N2, unsigned int nsteps, double nu, double delta, double L, _Complex double* u0, _Complex double* g, unsigned int print_freq, unsigned int starting_time, unsigned int nthreadsl, FILE* savefile);
 
 // compute energy, enstrophy and alpha
-int eea( int K1, int K2, int N1, int N2, unsigned int nsteps, double nu, double delta, double L, _Complex double* u0, _Complex double* g, unsigned int print_freq, unsigned int nthreads, FILE* savefile);
+int eea( int K1, int K2, int N1, int N2, unsigned int nsteps, double nu, double delta, double L, _Complex double* u0, _Complex double* g, unsigned int print_freq, unsigned int starting_time, unsigned int nthreads, FILE* savefile);
 
 // compute solution as a function of time, but do not print anything (useful for debugging)
 int quiet( int K1, int K2, int N1, int N2, unsigned int nsteps, double nu, double delta, double L, _Complex double* u0, _Complex double* g, unsigned int nthreads, FILE* savefile);