lhe_tridents_displacetime.cc

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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <stdhep_util.hh>
 
#include <gsl/gsl_rng.h>
#include <gsl/gsl_randist.h>
 
#include <unistd.h>
 
void remove_nulls(vector<stdhep_entry> *event)
{
  int i = 0;
  while (i < event->size()) {
    if (event->at(i).isthep == 0) {
      event->erase(event->begin() + i);
      for (int j = 0; j < event->size(); j++) {
        if (event->at(j).jmohep[0] > i)
          event->at(j).jmohep[0]--;
        if (event->at(j).jmohep[1] > i)
          event->at(j).jmohep[1]--;
        if (event->at(j).jdahep[0] > i)
          event->at(j).jdahep[0]--;
        if (event->at(j).jdahep[1] > i)
          event->at(j).jdahep[1]--;
      }
    }
    i++;
  }
}
 
void set_jdahep(vector<stdhep_entry> *event)
{
  for (int i = 0; i < event->size(); i++) {
    event->at(i).jdahep[0] = 0;
    event->at(i).jdahep[1] = 0;
    for (int j = 0; j < event->size(); j++) {
      if (event->at(j).jmohep[0] == i+1 || event->at(j).jmohep[1] == i+1) {
        if (event->at(i).jdahep[0] == 0)
          event->at(i).jdahep[0] = j+1;
        event->at(i).jdahep[1] = j+1;
      }
    }
  }
}
 
void displace_vertex(vector<stdhep_entry> *event, gsl_rng *r, double decay_length)
{
  int ap_id = -1;
  double vx[4];
  for (int i = 0; i < event->size(); i++) {
    if (event->at(i).idhep == 622) {
      if (ap_id != -1) {
        printf("multiple A' found\n");
        break;
      }
      ap_id = i;
      double gamma = event->at(i).phep[3]/event->at(i).phep[4];
      double beta = sqrt(1-pow(gamma,-2.0));
      double p = 0.0;
      for (int j = 0; j < 3; j++) p += event->at(i).phep[j]*event->at(i).phep[j];
      p = sqrt(p);
      double proper_time = gsl_ran_exponential(r, decay_length);
      double distance = gamma*beta*proper_time;
      for (int j = 0; j < 3; j++) vx[j] = distance * event->at(i).phep[j]/p;
      vx[3] = gamma*proper_time;
      //printf("gamma=%f p=%f distance=%f vx=%f,%f,%f\n",gamma,p,distance,vx[0],vx[1],vx[2]);
    }
  }
  if (ap_id < 0) printf("no A' found\n");
  else for (int i = 0; i < event->size(); i++) {
    if (event->at(i).jmohep[0] == ap_id+1 || event->at(i).jmohep[1] == ap_id+1) {
        for (int j = 0; j < 4; j++) event->at(i).vhep[j] = vx[j];
    }
  }
}
 
int main(int argc,char** argv)
{
  int nevhep;  
  vector<stdhep_entry> new_event;
 
  int rseed = 0;
  double decay_length = -1.0;
  int c;
 
  while ((c = getopt(argc,argv,"hs:l:")) != -1) 
    switch (c)
    {
      case 'h':
        printf("-h: print this help\n");
        printf("-s: RNG seed\n");
        printf("-l: A' decay length in mm\n");
        return(0);
        break;
      case 's':
        rseed = atoi(optarg);
        break;
      case 'l':
        decay_length = atof(optarg);
        break;
      case '?':
        printf("Invalid option or missing option argument; -h to list options\n");
        return(1);
      default:
        abort();
    }
 
  if (argc-optind < 2)
  {
    printf("<input stdhep filename> <output stdhep filename>\n");
    return 1;
  }
 
  FILE * in_file;
  in_file = fopen(argv[optind],"r");
 
  // initialize the RNG
  const gsl_rng_type * T;
  gsl_rng * r;
  gsl_rng_env_setup();
 
  T = gsl_rng_mt19937;
  r = gsl_rng_alloc (T);
  gsl_rng_set(r, rseed);
 
  int ostream = 0;
 
  open_write(argv[optind+1], ostream, 1000);
  nevhep = 1;
 
  printf("Applying decay length of %f mm\n", decay_length > 0 ? decay_length : 0.0);
 
  while (true) {
    char line[1000];
    bool found_event = false;
    while (fgets(line, 1000, in_file) != NULL) {
      if (strstr(line, "<event") != NULL) {
        found_event = true;
        break;
      }
    }
    if (!found_event) {
      fclose(in_file);
      close_write(ostream);
      return(0);
    }
 
    int nup;
 
    fgets(line, 1000, in_file);
    sscanf(line, "%d %*d %*f %*f %*f %*f", &nup);
    for (int i = 0; i < nup; i++) {
      struct stdhep_entry *temp = new struct stdhep_entry;
      fgets(line, 1000, in_file);
      int icolup0, icolup1;
      double phep0 = 100.0;
      char blah[1000];
      sscanf(line, "%d %d %d %d %*d %*d %lf %lf %lf %lf %lf %*f %*f", &(temp->idhep), &(temp->isthep), &(temp->jmohep[0]), &(temp->jmohep[1]), &(temp->phep[0]), &(temp->phep[1]), &(temp->phep[2]), &(temp->phep[3]), &(temp->phep[4]));
      //int status = sscanf(line,"%d %d %d %d %*d %*d %s",&(temp->idhep),&istup,&(temp->jmohep[0]),&(temp->jmohep[1]),blah);
      switch (temp->isthep) {
        case 1:
        case 2:
          break;
        case -1:
          temp->isthep = 3;
          break;
        default:
          temp->isthep = 0;
      }
      switch (temp->idhep) {
        case 611:
          temp->idhep = 11;
          break;
        case -611:
          temp->idhep = -11;
          break;
      }
      for (int j = 0; j < 4; j++) temp->vhep[j] = 0.0;
      for (int j = 0; j < 2; j++) temp->jdahep[j] = 0;
      new_event.push_back(*temp);
    }
    remove_nulls(&new_event);
    set_jdahep(&new_event);
    if (decay_length>0) displace_vertex(&new_event,r,decay_length);
    write_stdhep(&new_event,nevhep);
    write_file(ostream);
    nevhep++;
  }
}