/* monte carlo step of ghmc - evaluation stage */
void ghmc_mc()
{
INTEG_TRACE(fprintf(stderr,"%d: ghmc_mc:\n",this_node));
double boltzmann;
int ekin_update_flag = 0;
hamiltonian_calc(ekin_update_flag);
//make MC decision only on the master
if (this_node==0) {
ghmcdata.att++;
//metropolis algorithm
boltzmann = ghmcdata.hmlt_new - ghmcdata.hmlt_old;
if (boltzmann < 0)
boltzmann = 1.0;
else if (boltzmann > 30)
boltzmann = 0.0;
else
boltzmann = exp(-beta*boltzmann);
//fprintf(stderr,"old hamiltonian : %f, new hamiltonian: % f, boltzmann factor: %f\n",ghmcdata.hmlt_old,ghmcdata.hmlt_new,boltzmann);
if ( d_random() < boltzmann) {
ghmcdata.acc++;
ghmc_mc_res = GHMC_MOVE_ACCEPT;
} else {
ghmc_mc_res = GHMC_MOVE_REJECT;
}
}
//let all nodes know about the MC decision result
mpi_bcast_parameter(FIELD_GHMC_RES);
if (ghmc_mc_res == GHMC_MOVE_ACCEPT) {
save_last_state();
//fprintf(stderr,"%d: mc move accepted\n",this_node);
} else {
load_last_state();
//fprintf(stderr,"%d: mc move rejected\n",this_node);
//if the move is rejected we might need to resort particles according to the loaded configurations
cells_resort_particles(CELL_GLOBAL_EXCHANGE);
invalidate_obs();
if (ghmc_mflip == GHMC_MFLIP_ON) {
momentum_flip();
} else if (ghmc_mflip == GHMC_MFLIP_RAND) {
if (d_random() < 0.5) momentum_flip();
}
}
//fprintf(stderr,"%d: temp after mc: %f\n",this_node,calc_local_temp());
}
int tclcommand_load_state(ClientData data, Tcl_Interp *interp, int argc, char **argv)
{
#ifdef GHMC
Tcl_ResetResult(interp);
/* load last saved system state */
load_last_state();
cells_resort_particles(CELL_GLOBAL_EXCHANGE);
invalidate_obs();
return TCL_OK;
#else
INTEG_TRACE(fprintf(stderr,"%d: call to ghmc but not compiled in!\n",this_node));
return tclcommand_ghmc_print_usage(interp);
#endif
}
