cosmotool/src/loadRamses.cpp

/*+
This is CosmoTool (./src/loadRamses.cpp) -- Copyright (C) Guilhem Lavaux (2007-2014)

guilhem.lavaux@gmail.com

This software is a computer program whose purpose is to provide a toolbox for cosmological
data analysis (e.g. filters, generalized Fourier transforms, power spectra, ...)

This software is governed by the CeCILL license under French law and
abiding by the rules of distribution of free software.  You can  use, 
modify and/ or redistribute the software under the terms of the CeCILL
license as circulated by CEA, CNRS and INRIA at the following URL
"http://www.cecill.info". 

As a counterpart to the access to the source code and  rights to copy,
modify and redistribute granted by the license, users are provided only
with a limited warranty  and the software's author,  the holder of the
economic rights,  and the successive licensors  have only  limited
liability. 

In this respect, the user's attention is drawn to the risks associated
with loading,  using,  modifying and/or developing or reproducing the
software by the user in light of its specific status of free software,
that may mean  that it is complicated to manipulate,  and  that  also
therefore means  that it is reserved for developers  and  experienced
professionals having in-depth computer knowledge. Users are therefore
encouraged to load and test the software's suitability as regards their
requirements in conditions enabling the security of their systems and/or 
data to be ensured and,  more generally, to use and operate it in the 
same conditions as regards security. 

The fact that you are presently reading this means that you have had
knowledge of the CeCILL license and that you accept its terms.
+*/

#include <sys/types.h>
#include <regex.h>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <cassert>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>
#include "loadRamses.hpp"
#include "load_data.hpp"
#include "fortran.hpp"
#include <map>

using namespace std;

CosmoTool::GadgetData *CosmoTool::loadRamses(const char *name, bool quiet)
{
  GadgetData *gd = (GadgetData *)malloc(sizeof(GadgetData));
  int id = 1;
  uint32_t totPart = 0;
  
  if (!quiet)
    cout << "Detecting number of files and particles..." << endl;
  while (1)
    {
      ostringstream ss_fname;  
      ss_fname << name << setfill('0') << setw(5) << id;
      string fname = ss_fname.str();

      if (!quiet)
	cout <<  " ... " << fname << endl;

      try
	{
	  UnformattedRead infile(fname);
	  
	  int nCpu, ndim, nPar;
	  
	  infile.beginCheckpoint();
	  nCpu = max(1,infile.readInt32());
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  ndim = infile.readInt32();
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  nPar = infile.readInt32();
	  infile.endCheckpoint();
	  
	  if (!quiet)
	    cout << "    NUMCPU=" << nCpu <<  " NUMDIM=" << ndim << " NumPart=" << nPar << endl;
	  
	  totPart += nPar;
	  id++;
	}
      catch (const NoSuchFileException& e)
	{
	  break;
	}
    }

  assert (totPart <= ((~(size_t)0)/sizeof(ParticleState)));
  size_t memSize = sizeof(ParticleState)*(size_t)totPart;
  if (!quiet)
    cout << " Needing " << memSize / 1024 << " kBytes" << endl;
  gd->particles = (ParticleState *)malloc(memSize);
  assert(gd->particles != 0);
  gd->NumPart = totPart;
  gd->ntot_withmasses = totPart;
  gd->header.npart[0] = totPart;
  for (int k = 1; k < 6; k++)
    {
      gd->header.npart[k] = 0;
      gd->header.mass[k] = 0;
    }
  gd->header.num_files = id;
  gd->header.BoxSize = 200.0 * 1000; // kPc
  gd->header.Omega0 = 0.30; // ????
  gd->header.OmegaLambda = 0.70; // ????
  gd->header.HubbleParam = 0.70; // ????

  if (!quiet)
    cout << " Total number part=" << totPart << endl
	 << "Loading particles ..." << endl;

  uint32_t curPos = 0;
  id = 1;
  while (1)
    {
      ostringstream ss_fname;  
      ss_fname << name << setfill('0') << setw(5) << id;
      string fname = ss_fname.str();

      if (!quiet)
	cout <<  " ... " << id;
      cout.flush();
      
      try {
	UnformattedRead infile(fname);
	
	int nCpu, ndim, nPar;
	
	
	infile.beginCheckpoint();
	nCpu = infile.readInt32();
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	ndim = infile.readInt32();
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	nPar = infile.readInt32();
	infile.endCheckpoint();
	
	ParticleState *s = &gd->particles[curPos];
	
	for (uint32_t i = nPar; i > 0; i--,s++)
	  s->Mass = 1.0;
	
	s = &gd->particles[curPos];
	infile.beginCheckpoint();
	for (uint32_t i = nPar; i > 0; i--)
	  {
	    s->Pos[0] = infile.readReal32();
	    s->Pos[0] *= gd->header.BoxSize;
	    s++;
	  }
	infile.endCheckpoint();

	s = &gd->particles[curPos];
	infile.beginCheckpoint();
	for (uint32_t i = nPar; i > 0; i--)
	{
	  s->Pos[1] = infile.readReal32();
	  s->Pos[1] *= gd->header.BoxSize;
	  s++;
	}
	infile.endCheckpoint();

	s = &gd->particles[curPos];
	infile.beginCheckpoint();
	for (uint32_t i = nPar; i > 0; i--)
	  {
	    s->Pos[2] = infile.readReal32();
	    s->Pos[2] *= gd->header.BoxSize;
	    s++;
	  }
	infile.endCheckpoint();

 	infile.beginCheckpoint();
	for (uint32_t i = 0; i < nPar; i++)
	  {
	    gd->particles[curPos+i].Vel[0] = infile.readReal32();
	  }
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	for (uint32_t i = 0; i < nPar; i++)
	  {
	    gd->particles[curPos+i].Vel[1] = infile.readReal32();
	  }
 	infile.endCheckpoint();

 	infile.beginCheckpoint();
	for (uint32_t i = 0; i < nPar; i++)
	  {
	    gd->particles[curPos+i].Vel[2] = infile.readReal32();
	  }
	infile.endCheckpoint();

	curPos += nPar;
      }
      catch (const NoSuchFileException& e)
	{
	  break;
	}

 
      id++;
    }

  if (!quiet)
    cout << endl;

  return gd;
}

typedef struct 
{
  double unitLength;
  double aexp;
  double boxSize;
  double unit_t;
  double omega_m;
  double omega_lambda;
} InfoData;

int readInfoFile(const char *basename, int outputId, InfoData& info)
{
  ostringstream ss_fname;  
  ss_fname << basename << "/info_" << setfill('0') << setw(5) << outputId << ".txt";

//  cout << "Opening info file " << ss_fname.str() << endl;
  ifstream infile(ss_fname.str().c_str());
  if (!infile)
    return 0;

  int err;
  regex_t unit_l_rx;

  //  const char *pattern = "^unit_l[ ]*=[ ]*([0-9\\.E+\\-]+)";
  const char *pattern = "^([A-Za-z_]+)[ ]*=[ ]*([0-9\\.E+\\-]+)";

  err = regcomp (&unit_l_rx, pattern, REG_EXTENDED);
//  cout << unit_l_rx.re_nsub << endl;
  if (err)
    {
      char errString[255];
      regerror(err, &unit_l_rx, errString, sizeof(errString));
      cout << errString << endl;
      abort();
    }

  map<string,double> infoMap;
  string line;
  while (getline(infile, line))
    {
      regmatch_t allMatch[4];
      if (!regexec(&unit_l_rx, line.c_str(), 4, allMatch, 0))
	{
	  uint32_t start0 = allMatch[1].rm_so, end0 = allMatch[1].rm_eo;
	  uint32_t start1 = allMatch[2].rm_so, end1 = allMatch[2].rm_eo;

	  string keyword = line.substr(start0, end0-start0);
	  istringstream iss(line.substr(start1, end1-start1));
	  double unitLength;

	  iss >> unitLength;

	  infoMap[keyword] = unitLength;
	}
    }
  
  regfree(&unit_l_rx);

  info.unitLength = infoMap["unit_l"];
  info.aexp = infoMap["aexp"];
  info.boxSize = infoMap["boxlen"];
  info.unit_t = infoMap["unit_t"];
  info.omega_m = infoMap["omega_m"];
  info.omega_lambda = infoMap["omega_l"];

  return 1;
}

CosmoTool::SimuData *CosmoTool::loadRamsesSimu(const char *basename, int outputId, int cpuid, bool dp, int flags)
{
  CosmoTool::SimuData *data = new CosmoTool::SimuData();

  int id = 1;
  uint32_t totPart = 0;
  int nCpu = 0;
  InfoData info;

  static const double CM_IN_MPC = 3.08e24;

  if (!readInfoFile(basename, outputId, info))
    return 0;

  double hubble = info.aexp*info.aexp/info.unit_t / (1e5/CM_IN_MPC);
  double L0 = info.boxSize*info.unitLength*hubble/100/CM_IN_MPC/info.aexp;
  double unit_vel = L0*100/info.aexp;
  
  while (1)
    {
      ostringstream ss_fname;
      ss_fname << basename << "/part_" << setfill('0') << setw(5) << outputId << ".out" << setfill('0') << setw(5) << id;
      string fname = ss_fname.str();

      try
        {
          UnformattedRead infile(fname);

          int ndim, nPar;

          infile.beginCheckpoint();
          nCpu = max(1,infile.readInt32());
          infile.endCheckpoint();

          infile.beginCheckpoint();
          ndim = infile.readInt32();
          infile.endCheckpoint();

          infile.beginCheckpoint();
          nPar = infile.readInt32();
          infile.endCheckpoint();

          totPart += nPar;
          id++;
        }
      catch (const NoSuchFileException& e)
        {
          break;
        }
    }


  data->BoxSize = L0;
  data->time = info.aexp;
  data->NumPart = 0;
  data->TotalNumPart = totPart;
  data->Hubble = hubble;
  data->Omega_M = info.omega_m;
  data->Omega_Lambda = info.omega_lambda;

  if (flags == 0)
    return data;

  if (cpuid < 0)
    cpuid = 1;
  else cpuid++;

  uint32_t curPos = 0;
  
  ostringstream ss_fname;
  ss_fname << basename << "/part_" << setfill('0') << setw(5) << outputId << ".out" << setfill('0') << setw(5) << cpuid;
  
  string fname = ss_fname.str();
    
  try
    {
      UnformattedRead infile(fname);
      
      int nCpu, ndim, nPar;
      
      infile.beginCheckpoint();
      nCpu = infile.readInt32();
      infile.endCheckpoint();
      
      infile.beginCheckpoint();
      ndim = infile.readInt32();
      infile.endCheckpoint();
      
      infile.beginCheckpoint();
      data->NumPart = nPar = infile.readInt32();
      infile.endCheckpoint();

      infile.beginCheckpoint();
      for (int i = 0; i < 4; i++) infile.readInt32();
      infile.endCheckpoint();
      
      infile.beginCheckpoint();
      infile.readInt32();
      infile.endCheckpoint();
      
      infile.beginCheckpoint();
      infile.readReal64();
      infile.endCheckpoint();

      infile.beginCheckpoint();
      infile.readReal64();
      infile.endCheckpoint();
      
      infile.beginCheckpoint();
      infile.readInt32();
      infile.endCheckpoint();
      
      if (flags & NEED_POSITION)
	{
	  data->Pos[0] = new float[nPar];
	  data->Pos[1] = new float[nPar];
	  data->Pos[2] = new float[nPar];
	}
      if (flags & NEED_VELOCITY)
	{
	  data->Vel[0] = new float[nPar];
	  data->Vel[1] = new float[nPar];
	  data->Vel[2] = new float[nPar];
	}
      if (flags & NEED_GADGET_ID)
	{
	  data->Id = new long[nPar];
	}

      for (int k = 0; k < 3; k++)
	{
	  infile.beginCheckpoint();
	  if (flags & NEED_POSITION)
	    {
	      for (uint32_t i = 0; i < nPar; i++)
		{
		  data->Pos[k][i] = dp ? infile.readReal64() : infile.readReal32();
		  data->Pos[k][i] *= data->BoxSize;
		}
	      infile.endCheckpoint();
	    }
	  else
	    infile.endCheckpoint(true);
	}
      
      for (int k = 0; k < 3; k++) {
	infile.beginCheckpoint();
	if (flags & NEED_VELOCITY)
	  {
	    for (uint32_t i = 0; i < nPar; i++)
	      {
		data->Vel[k][i] = dp ? infile.readReal64() : infile.readReal32();
		data->Vel[k][i] *= unit_vel;
	      }
	    infile.endCheckpoint();
	  }
	else
	  infile.endCheckpoint(true);
      }
      
      float minMass = INFINITY;
      infile.beginCheckpoint();
      for (uint32_t i = nPar; i > 0; i--)
	{
	  float dummyF = dp ? infile.readReal64() : infile.readReal32();
	  if (dummyF < minMass) minMass = dummyF;
	}
      infile.endCheckpoint();
      
      infile.beginCheckpoint();
      if (flags & NEED_GADGET_ID)
	{
	  for (uint32_t i = 0; i < nPar; i++)
	    data->Id[i] = infile.readInt32();
	  
	  infile.endCheckpoint();
	}
      else
	infile.endCheckpoint(true);
      
      curPos += nPar;
    }
  catch (const NoSuchFileException& e)  
    {
//	cerr << "No such file " << fname << endl;
      delete data;
      return 0;
    }
  
  return data;
}







CosmoTool::PurePositionData *CosmoTool::loadRamsesPosition(const char *basename, int outputId, bool quiet, bool dp)
{
  PurePositionData *gd = (PurePositionData *)malloc(sizeof(PurePositionData));
  int id = 1;
  uint32_t totPart = 0;
  int nCpu = 0;
  InfoData info;
  
  static const double CM_IN_MPC = 3.08e24;

  if (!readInfoFile(basename, outputId, info))
    return 0;

  double hubble = info.aexp*info.aexp/info.unit_t / (1e5/CM_IN_MPC);
  double L0 = info.boxSize*info.unitLength*hubble/100/CM_IN_MPC/info.aexp;
  if (!quiet)
    {
      cout << "L0=" << L0 << " Mpc" << endl;
      cout << "H=" << hubble << " km/s/Mpc" << endl;
    }

  if (!quiet)
    cout << "Detecting number of files and particles..." << endl;
  while (1)
    {
      ostringstream ss_fname;  
      ss_fname << basename << "/part_" << setfill('0') << setw(5) << outputId << ".out" << setfill('0') << setw(5) << id;
      string fname = ss_fname.str();
      
      if (!quiet)
	cout <<  " ... " << fname << endl;
      

      try
	{
	  UnformattedRead infile(fname);
	  
	  int ndim, nPar;
	  
	  infile.beginCheckpoint();
	  nCpu = max(1,infile.readInt32());
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  ndim = infile.readInt32();
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  nPar = infile.readInt32();
	  infile.endCheckpoint();
	  
	  if (!quiet)
	    cout << "    NUMCPU=" << nCpu <<  " NUMDIM=" << ndim << " NumPart=" << nPar << endl;
	  
	  totPart += nPar;
	  id++;
	}
      catch (const NoSuchFileException& e)
	{
	  break;
	}

    }

  assert (totPart <= ((~(size_t)0)/sizeof(FCoordinates)));
  size_t memSize = sizeof(FCoordinates)*(size_t)(totPart+totPart/nCpu);
  if (!quiet)
    cout << " Needing " << memSize / 1024 << " kBytes" << endl;
  gd->pos = (FCoordinates *)malloc(sizeof(FCoordinates)*totPart);
  assert(gd->pos != 0);
  gd->NumPart = totPart;
  gd->BoxSize = L0*1000; 
  gd->hubble = hubble;

  if (!quiet)
    cout << " Total number part=" << totPart << endl
	 << "Loading particles ..." << endl;
  
  uint32_t curPos = 0;
  id = 1;
  while (1)
    {
      ostringstream ss_fname;  
      ss_fname << basename << "/part_" << setfill('0') << setw(5) << outputId << ".out" << setfill('0') << setw(5) << id;
     
      string fname = ss_fname.str();
      int *idP;

      if (!quiet)
	(cout <<  " ... " << id).flush();
      
      try
	{
	  UnformattedRead infile(fname);
	  
	  int nCpu, ndim, nPar;
	  
	  infile.beginCheckpoint();
	  nCpu = infile.readInt32();
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  ndim = infile.readInt32();
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  nPar = infile.readInt32();
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
          for (int i = 0; i < 4; i++) infile.readInt32();
	  infile.endCheckpoint();

	  infile.beginCheckpoint();
          infile.readInt32();
	  infile.endCheckpoint();

	  infile.beginCheckpoint();
          infile.readReal64();
	  infile.endCheckpoint();

	  infile.beginCheckpoint();
          infile.readReal64();
	  infile.endCheckpoint();

	  infile.beginCheckpoint();
          infile.readInt32();
	  infile.endCheckpoint();

	  FCoordinates *s = new FCoordinates[nPar];
	  
	  for (int k = 0; k < 3; k++)
	    {
	      infile.beginCheckpoint();
	      for (uint32_t i = 0; i < nPar; i++)
		{
		  s[i][k] = dp ? infile.readReal64() : infile.readReal32();
		  s[i][k] *= gd->BoxSize;
		}
	      infile.endCheckpoint();
	    }

	  // SKIP VELOCITIES
	  for (int k = 0; k < 3; k++) {	
	    infile.beginCheckpoint();
	    for (uint32_t i = nPar; i > 0; i--)
	      {
		(dp ? infile.readReal64() : infile.readReal32());
	      }
	    infile.endCheckpoint();
	  }
	  
	  float minMass = INFINITY;
	  infile.beginCheckpoint();
	  for (uint32_t i = nPar; i > 0; i--)
	    {
	      float dummyF = dp ?  infile.readReal64() : infile.readReal32();
	      if (dummyF < minMass) minMass = dummyF;
	    }
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  for (uint32_t i = 0; i < nPar; i++)
	    {
	      int id = infile.readInt32();
	      id--;
	      assert(id >= 0);
	      assert(id < totPart);
	      memcpy(&gd->pos[id], &s[i], sizeof(FCoordinates));
	    }
	  infile.endCheckpoint();
      
	  delete[] s;
	  
	  curPos += nPar;
	} catch (const NoSuchFileException& e)
	{
	  break;
	}
      id++;
    }

  if (!quiet)
    cout << endl;

  return gd;
}

CosmoTool::PhaseSpaceData *CosmoTool::loadRamsesPhase(const char *basename, int outputId, bool quiet)
{
  PhaseSpaceData *gd = (PhaseSpaceData *)malloc(sizeof(PhaseSpaceData));
  int id = 1;
  uint32_t totPart = 0;
  int nCpu = 0;
  InfoData info;
  
  static const double CM_IN_MPC = 3.08e24;

  if (!readInfoFile(basename, outputId, info))
    return 0;

  double hubble = info.aexp*info.aexp/info.unit_t / (1e5/CM_IN_MPC);
  double L0 = info.boxSize*info.unitLength*hubble/(100*CM_IN_MPC)/info.aexp;
  double unit_vel = 100*L0/info.aexp;
  if (!quiet) {
    cout << "L0=" << L0 << " Mpc" << endl;
    cout << "H=" << hubble << " km/s/Mpc" << endl;
    cout << "unit_vel=" << unit_vel << " km/s" << endl;
  }

  if (!quiet)
    cout << "Detecting number of files and particles..." << endl;
  while (1)
    {
      ostringstream ss_fname;  
      ss_fname << basename << "/part_" << setfill('0') << setw(5) << outputId << ".out" << setfill('0') << setw(5) << id;
      string fname = ss_fname.str();
      
      if (!quiet)
	cout <<  " ... " << fname << endl;
      

      try
	{
	  UnformattedRead infile(fname);
	  
	  int ndim, nPar;
	  
	  infile.beginCheckpoint();
	  nCpu = max(1,infile.readInt32());
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  ndim = infile.readInt32();
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  nPar = infile.readInt32();
	  infile.endCheckpoint();
	  
	  if (!quiet)
	    cout << "    NUMCPU=" << nCpu <<  " NUMDIM=" << ndim << " NumPart=" << nPar << endl;
	  
	  totPart += nPar;
	  id++;
	}
      catch (const NoSuchFileException& e)
	{
	  break;
	}

    }

  assert (totPart <= ((~(size_t)0)/sizeof(FCoordinates)));
  size_t memSize = sizeof(FCoordinates)*(size_t)(totPart+totPart/nCpu);
  if (!quiet)
    cout << " Needing " << memSize / 1024 << " kBytes" << endl;
  gd->pos = (FCoordinates *)malloc(sizeof(FCoordinates)*totPart);
  assert(gd->pos != 0);
  gd->vel = (FCoordinates *)malloc(sizeof(FCoordinates)*totPart);
  assert(gd->vel != 0);
  gd->NumPart = totPart;
  gd->BoxSize = L0*1000; 
  gd->hubble = hubble;
  
  if (!quiet)
    cout << " Total number part=" << totPart << endl
	 << "Loading particles ..." << endl;
  
  uint32_t curPos = 0;
  id = 1;
  while (1)
    {
      ostringstream ss_fname;  
      ss_fname << basename << "/part_" << setfill('0') << setw(5) << outputId << ".out" << setfill('0') << setw(5) << id;
     
      string fname = ss_fname.str();
      int *idP;

      if (!quiet)
	(cout <<  " ... " << id).flush();
      
      try
	{
	  UnformattedRead infile(fname);
	  
	  int nCpu, ndim, nPar;
	  
	  infile.beginCheckpoint();
	  nCpu = infile.readInt32();
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  ndim = infile.readInt32();
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  nPar = infile.readInt32();
	  infile.endCheckpoint();
	  

	  FCoordinates *s = new FCoordinates[nPar];
	  FCoordinates *vel = new FCoordinates[nPar];
	  
	  for (int k = 0; k < 3; k++)
	    {
	      infile.beginCheckpoint();
	      for (uint32_t i = 0; i < nPar; i++)
		{
		  s[i][k] = infile.readReal32();
		  s[i][k] *= gd->BoxSize;
		}
	      infile.endCheckpoint();
	    }

	  // SKIP VELOCITIES
	  for (int k = 0; k < 3; k++) {	
	    infile.beginCheckpoint();
	    for (uint32_t i = 0; i < nPar; i++)
	      {
		vel[i][k] = infile.readReal32()*unit_vel;
	      }
	    infile.endCheckpoint();
	  }
	  
	  float minMass = INFINITY;
	  infile.beginCheckpoint();
	  for (uint32_t i = nPar; i > 0; i--)
	    {
	      float dummyF = infile.readReal32();
	      if (dummyF < minMass) minMass = dummyF;
	    }
	  infile.endCheckpoint();
	  
	  infile.beginCheckpoint();
	  for (uint32_t i = 0; i < nPar; i++)
	    {
	      int id = infile.readInt32();
	      id--;
	      assert(id >= 0);
	      assert(id < totPart);
	      memcpy(&gd->pos[id], &s[i], sizeof(FCoordinates));
	      memcpy(&gd->vel[id], &vel[i], sizeof(FCoordinates));
	    }
	  infile.endCheckpoint();
      
	  delete[] vel;
	  delete[] s;
	  
	  curPos += nPar;
	} catch (const NoSuchFileException& e)
	{
	  break;
	}
      id++;
    }

  if (!quiet)
    cout << endl;

  return gd;
}


CosmoTool::PhaseSpaceDataID *CosmoTool::loadRamsesPhase1(const char *basename, int outputId, int cpuid, bool dp, bool quiet)
{
  PhaseSpaceDataID *gd = (PhaseSpaceDataID *)malloc(sizeof(PhaseSpaceDataID));
  int id = 1;
  uint32_t totPart = 0;
  int nCpu = 0;
  InfoData info;
  
  static const double CM_IN_MPC = 3.08e24;

  if (!readInfoFile(basename, outputId, info))
    return 0;

  double hubble = info.aexp*info.aexp/info.unit_t / (1e5/CM_IN_MPC);
  double L0 = info.boxSize*info.unitLength*hubble/100/CM_IN_MPC/info.aexp;
  double unit_vel = 100*L0/info.aexp;
  if (!quiet) {
    cout << "L0=" << L0 << " Mpc" << endl;
    cout << "H=" << hubble << " km/s/Mpc" << endl;
    cout << "unitvel=" << unit_vel << " km/s" << endl;
  }

  if (!quiet)
    cout << "Detecting number of files and particles..." << endl;
  id = cpuid;
  {
    ostringstream ss_fname;  
    ss_fname << basename << "/part_" << setfill('0') << setw(5) << outputId << ".out" << setfill('0') << setw(5) << id;
    string fname = ss_fname.str();
    
    if (!quiet)
      cout <<  " ... " << fname << endl;
    
    
    try
      {
	UnformattedRead infile(fname);
	
	int ndim, nPar;
	
	infile.beginCheckpoint();
	nCpu = max(1,infile.readInt32());
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	ndim = infile.readInt32();
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	nPar = infile.readInt32();
	infile.endCheckpoint();
	
	if (!quiet)
	  cout << "    NUMCPU=" << nCpu <<  " NUMDIM=" << ndim << " NumPart=" << nPar << endl;
	
	totPart += nPar;
	id++;
      }
    catch (const NoSuchFileException& e)
      {
	return 0;
      }
  }
  
  assert (totPart <= ((~(size_t)0)/sizeof(FCoordinates)));
  size_t memSize = sizeof(FCoordinates)*(size_t)(totPart+totPart/nCpu);
  if (!quiet)
    cout << " Needing " << memSize / 1024 << " kBytes" << endl;
  gd->pos = (FCoordinates *)malloc(sizeof(FCoordinates)*totPart);
  assert(gd->pos != 0);
  gd->vel = (FCoordinates *)malloc(sizeof(FCoordinates)*totPart);
  assert(gd->vel != 0);
  gd->ID = (int *)malloc(sizeof(int)*totPart);
  assert(gd->ID != 0);
  gd->NumPart = totPart;
  gd->BoxSize = L0*1000; 
  gd->hubble = hubble;
  
  uint32_t curPos = 0;
  id = cpuid;
  {
    ostringstream ss_fname;  
    ss_fname << basename << "/part_" << setfill('0') << setw(5) << outputId << ".out" << setfill('0') << setw(5) << id;
    
    string fname = ss_fname.str();
    int *idP;
    
    if (!quiet)
      (cout <<  " ... " << id).flush();
    
    try
      {
	UnformattedRead infile(fname);
	
	int nCpu, ndim, nPar;
	
	infile.beginCheckpoint();
	nCpu = infile.readInt32();
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	ndim = infile.readInt32();
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	nPar = infile.readInt32();
	infile.endCheckpoint();

	infile.beginCheckpoint();
	for (int i = 0; i < 4; i++) infile.readInt32();
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	infile.readInt32();
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	infile.readReal64();
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	infile.readReal64();
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	infile.readInt32();
	infile.endCheckpoint();

	gd->pos = new FCoordinates[nPar];
	gd->vel = new FCoordinates[nPar];
	
	for (int k = 0; k < 3; k++)
	  {
	    infile.beginCheckpoint();
	    for (uint32_t i = 0; i < nPar; i++)
	      {
		gd->pos[i][k] = (dp ? infile.readReal64() : infile.readReal32())*gd->BoxSize;
	      }
	    infile.endCheckpoint();
	  }
	
	// SKIP VELOCITIES
	for (int k = 0; k < 3; k++) {	
	  infile.beginCheckpoint();
	  for (uint32_t i = 0; i < nPar; i++)
	    {
	      gd->vel[i][k] = (dp ? infile.readReal64() : infile.readReal32())*unit_vel;
	    }
	  infile.endCheckpoint();
	}
	
	float minMass = INFINITY;
	infile.beginCheckpoint();
	for (uint32_t i = nPar; i > 0; i--)
	  {
	    float dummyF = (dp ? infile.readReal64() : infile.readReal32());
	    if (dummyF < minMass) minMass = dummyF;
	  }
	infile.endCheckpoint();
	
	infile.beginCheckpoint();
	for (uint32_t i = 0; i < nPar; i++)
	  {
	    gd->ID[i] = infile.readInt32();
	  }
	infile.endCheckpoint();
	
	curPos += nPar;
      } 
    catch (const NoSuchFileException& e) 
      {
	return 0;
      }
  }
  
  if (!quiet)
    cout << endl;

  return gd;
}