NVIDIA-GPU-Bootcamp-Training/hpc/nways/nways_labs/nways_MD/English/C/source_code/openmp/dcdread.h

// Copyright (c) 2021 NVIDIA Corporation.  All rights reserved. 
using namespace std;

void dcdreadhead(int *natom, int *nframes, std::istream &infile) {

 infile.seekg(8,ios::beg);
 infile.read((char*)nframes, sizeof(int));
 infile.seekg(64*4,ios::cur);
 infile.read((char*)natom, sizeof(int));
 infile.seekg(1*8,ios::cur);
 return;
}

void dcdreadframe(double *x, double *y, double *z, std::istream &infile,
    int natom, double& xbox,double& ybox,double& zbox){

  double d[6];
  for (int i=0;i<6;i++) {
      infile.read((char*)&d[i], sizeof(double));
  }
  xbox=d[0];
  ybox=d[2];
  zbox=d[5];
  float a,b,c;
  infile.seekg(1*8,ios::cur);
  for (int i=0;i<natom;i++){
      infile.read((char*)&a, sizeof(float));
      x[i]=a;
  }
  infile.seekg(1*8,ios::cur);
  for (int i=0;i<natom;i++) {
      infile.read((char*)&b, sizeof(float));
      y[i]=b;
  }
  infile.seekg(1*8,ios::cur);
  for (int i=0;i<natom;i++) {
      infile.read((char*)&c, sizeof(float));
      z[i]=c;
  }
  infile.seekg(1*8,ios::cur);

  return;
}