PViewDataGModelIO.cpp

// Gmsh - Copyright (C) 1997-2013 C. Geuzaine, J.-F. Remacle
//
// See the LICENSE.txt file for license information. Please report all
// bugs and problems to the public mailing list <gmsh@geuz.org>.

#include "GmshConfig.h"
#include "GmshMessage.h"
#include "PViewDataGModel.h"
#include "MVertex.h"
#include "MElement.h"
#include "Numeric.h"
#include "StringUtils.h"
#include "OS.h"

bool PViewDataGModel::addData(GModel *model, std::map<int, std::vector<double> > &data,
                              int step, double time, int partition, int numComp)
{
  if(data.empty()) return false;

  if (numComp < 0){
    numComp = 9;
    for(std::map<int, std::vector<double> >::iterator it = data.begin();
        it != data.end(); it++)
      numComp = std::min(numComp, (int)it->second.size());
  }

  while(step >= (int)_steps.size())
    _steps.push_back(new stepData<double>(model, numComp));
  _steps[step]->fillEntities();
  _steps[step]->computeBoundingBox();
  _steps[step]->setTime(time);

  int numEnt = (_type == NodeData) ? model->getNumMeshVertices() :
    model->getNumMeshElements();
  _steps[step]->resizeData(numEnt);

  for(std::map<int, std::vector<double> >::iterator it = data.begin();
      it != data.end(); it++){
    int mult = it->second.size() / numComp;
    double *d  = _steps[step]->getData(it->first, true, mult);
    for(int j = 0; j < numComp * mult; j++)
      d[j] = it->second[j];
  }
  if(partition >= 0)
    _steps[step]->getPartitions().insert(partition);
  finalize();
  return true;
}

void PViewDataGModel::destroyData()
{
  for(unsigned int i = 0; i < _steps.size(); i++)
    _steps[i]->destroyData();
}

bool PViewDataGModel::readMSH(const std::string &viewName, const std::string &fileName,
                              int fileIndex, FILE *fp, bool binary, bool swap,
                              int step, double time, int partition, int numComp,
                              int numEnt, const std::string &interpolationScheme)
{
  Msg::Info("Reading view `%s' step %d (time %g) partition %d: %d records",
            viewName.c_str(), step, time, partition, numEnt);

  while(step >= (int)_steps.size())
    _steps.push_back(new stepData<double>(GModel::current(), numComp));
  _steps[step]->fillEntities();
  _steps[step]->computeBoundingBox();
  _steps[step]->setFileName(fileName);
  _steps[step]->setFileIndex(fileIndex);
  _steps[step]->setTime(time);

  /*
  // if we already have maxSteps for this view, return
  int numSteps = 0, maxSteps = 1000000000;
  for(unsigned int i = 0; i < _steps.size(); i++)
    numSteps += _steps[i]->getNumData() ? 1 : 0;
  if(numSteps > maxSteps) return true;
  */

  _steps[step]->resizeData(numEnt);

  Msg::ResetProgressMeter();
  for(int i = 0; i < numEnt; i++){
    int num;
    if(binary){
      if(fread(&num, sizeof(int), 1, fp) != 1) return false;
      if(swap) SwapBytes((char*)&num, sizeof(int), 1);
    }
    else{
      if(fscanf(fp, "%d", &num) != 1) return false;
    }
    int mult = 1;
    if(_type == ElementNodeData || _type == GaussPointData){
      if(binary){
        if(fread(&mult, sizeof(int), 1, fp) != 1) return false;
        if(swap) SwapBytes((char*)&mult, sizeof(int), 1);
      }
      else{
        if(fscanf(fp, "%d", &mult) != 1) return false;
      }
    }
    double *d = _steps[step]->getData(num, true, mult);
    if(binary){
      if((int)fread(d, sizeof(double), numComp * mult, fp) != numComp * mult)
        return false;
      if(swap) SwapBytes((char*)d, sizeof(double), numComp * mult);
    }
    else{
      for(int j = 0; j < numComp * mult; j++)
        if(fscanf(fp, "%lf", &d[j]) != 1) return false;
    }
    // compute min/max here to avoid calling finalize(true) later:
    // this would be very slow for large multi-step, multi-partition
    // datasets (since we would recompute the min/max for all the
    // previously loaded steps/partitions, and thus loop over all the
    // elements many times)
    for(int j = 0; j < mult; j++){
      double val = ComputeScalarRep(numComp, &d[numComp * j]);
      _steps[step]->setMin(std::min(_steps[step]->getMin(), val));
      _steps[step]->setMax(std::max(_steps[step]->getMax(), val));
      _min = std::min(_min, val);
      _max = std::max(_max, val);
    }
    if(numEnt > 100000)
      Msg::ProgressMeter(i + 1, numEnt, true, "Reading data");
  }

  if(partition >= 0)
    _steps[step]->getPartitions().insert(partition);

  finalize(false, interpolationScheme);
  return true;
}

bool PViewDataGModel::writeMSH(const std::string &fileName, double version, bool binary,
                               bool savemesh, bool multipleView)
{
  if(_steps.empty()) return true;

  if(hasMultipleMeshes()){
    Msg::Error("Export not done for multi-mesh views");
    return false;
  }

  GModel *model = _steps[0]->getModel();

  bool writeNodesAndElements = savemesh;
  FILE *fp;
  if(writeNodesAndElements){
    if(!model->writeMSH(fileName, version, binary, false, false, 1.0, 0,
                        0, multipleView)) return false;
    // append data
    fp = Fopen(fileName.c_str(), binary ? "ab" : "a");
    if(!fp){
      Msg::Error("Unable to open file '%s'", fileName.c_str());
      return false;
    }
  }
  else{
    if(multipleView){
      fp = Fopen(fileName.c_str(), binary ? "ab" : "a");
      if(!fp){
        Msg::Error("Unable to open file '%s'", fileName.c_str());
        return false;
      }
    }
    else{
      fp = Fopen(fileName.c_str(), binary ? "wb" : "w");
      if(!fp){
        Msg::Error("Unable to open file '%s'", fileName.c_str());
        return false;
      }
      fprintf(fp, "$MeshFormat\n");
      fprintf(fp, "%g %d %d\n", 2.2, binary ? 1 : 0, (int)sizeof(double));
      if(binary){
        int one = 1;
        fwrite(&one, sizeof(int), 1, fp);
        fprintf(fp, "\n");
      }
      fprintf(fp, "$EndMeshFormat\n");
    }
  }

  if(haveInterpolationMatrices()){
    fprintf(fp, "$InterpolationScheme\n");
    fprintf(fp, "\"INTERPOLATION_SCHEME\"\n");
    fprintf(fp, "%d\n", (int)_interpolation.size());
    for(interpolationMatrices::iterator it = _interpolation.begin();
        it != _interpolation.end(); it++){
      if(it->second.size() >= 2){
        fprintf(fp, "%d\n2\n", it->first);
        for(int mat = 0; mat < 2; mat++){
          int m = it->second[mat]->size1(), n = it->second[mat]->size2();
          fprintf(fp, "%d %d\n", m, n);
          for(int i = 0; i < m; i++){
            for(int j = 0; j < n; j++)
              fprintf(fp, "%.16g ", it->second[mat]->get(i, j));
            fprintf(fp, "\n");
          }
        }
      }
    }
    fprintf(fp, "$EndInterpolationScheme\n");
  }

  for(unsigned int step = 0; step < _steps.size(); step++){
    int numEnt = 0, numComp = _steps[step]->getNumComponents();
    for(int i = 0; i < _steps[step]->getNumData(); i++)
      if(_steps[step]->getData(i)) numEnt++;
    if(numEnt){
      if(_type == NodeData){
        fprintf(fp, "$NodeData\n");
        fprintf(fp, "1\n\"%s\"\n", getName().c_str());
        fprintf(fp, "1\n%.16g\n", _steps[step]->getTime());
        fprintf(fp, "3\n%d\n%d\n%d\n", step, numComp, numEnt);
        for(int i = 0; i < _steps[step]->getNumData(); i++){
          if(_steps[step]->getData(i)){
            MVertex *v = _steps[step]->getModel()->getMeshVertexByTag(i);
            if(!v){
              Msg::Error("Unknown vertex %d in data", i);
              fclose(fp);
              return false;
            }
            int num = v->getIndex();
            if(binary){
              fwrite(&num, sizeof(int), 1, fp);
              fwrite(_steps[step]->getData(i), sizeof(double), numComp, fp);
            }
            else{
              fprintf(fp, "%d", num);
              for(int k = 0; k < numComp; k++)
                fprintf(fp, " %.16g", _steps[step]->getData(i)[k]);
              fprintf(fp, "\n");
            }
          }
        }
        if(binary) fprintf(fp, "\n");
        fprintf(fp, "$EndNodeData\n");
      }
      else{
        if(_type == ElementNodeData)
          fprintf(fp, "$ElementNodeData\n");
        else
          fprintf(fp, "$ElementData\n");
        if(haveInterpolationMatrices())
          fprintf(fp, "2\n\"%s\"\n\"INTERPOLATION_SCHEME\"\n", getName().c_str());
        else
          fprintf(fp, "1\n\"%s\"\n", getName().c_str());

        fprintf(fp, "1\n%.16g\n", _steps[step]->getTime());
        fprintf(fp, "3\n%d\n%d\n%d\n", step, numComp, numEnt);
        for(int i = 0; i < _steps[step]->getNumData(); i++){
          if(_steps[step]->getData(i)){
            MElement *e = model->getMeshElementByTag(i);
            if(!e){
              Msg::Error("Unknown element %d in data", i);
              fclose(fp);
              return false;
            }
            int mult = _steps[step]->getMult(i);
            int num = model->getMeshElementIndex(e);
            if(binary){
              fwrite(&num, sizeof(int), 1, fp);
              if(_type == ElementNodeData)
                fwrite(&mult, sizeof(int), 1, fp);
              fwrite(_steps[step]->getData(i), sizeof(double), numComp * mult, fp);
            }
            else{
              fprintf(fp, "%d", num);
              if(_type == ElementNodeData)
                fprintf(fp, " %d", mult);
              for(int k = 0; k < numComp * mult; k++)
                fprintf(fp, " %.16g", _steps[step]->getData(i)[k]);
              fprintf(fp, "\n");
            }
          }
        }
        if(binary) fprintf(fp, "\n");
        if(_type == ElementNodeData)
          fprintf(fp, "$EndElementNodeData\n");
        else
          fprintf(fp, "$EndElementData\n");
      }
    }
  }

  fclose(fp);
  return true;
}

#if defined(HAVE_MED)

extern "C" {
#include <med.h>
}

#if (MED_MAJOR_NUM == 3)
// To avoid too many ifdefs below we use defines for the bits of the
// API that did not change too much between MED2 and MED3. If we
// remove MED2 support at some point, please remove these defines and
// replace the symbols accordingly.
#define med_geometrie_element med_geometry_type
#define med_entite_maillage med_entity_type
#define med_type_champ med_field_type
#define MED_TAILLE_NOM MED_NAME_SIZE
#define MED_TAILLE_PNOM MED_SNAME_SIZE
#define MED_LECTURE MED_ACC_RDONLY
#define MED_LECTURE_AJOUT MED_ACC_RDEXT
#define MED_NOEUD MED_NODE
#define MED_MAILLE MED_CELL
#define MED_NOEUD_MAILLE MED_NODE_ELEMENT
#define MED_NOPFL MED_NO_PROFILE
#define MEDouvrir MEDfileOpen
#define MEDfermer MEDfileClose
#define MEDnChamp MEDfieldnComponent
#define MEDnValProfil MEDprofileSizeByName
#endif

extern int med2mshElementType(med_geometrie_element med);
extern int med2mshNodeIndex(med_geometrie_element med, int k);

std::vector<std::string> medGetFieldNames(const std::string &fileName)
{
  std::vector<std::string> fieldNames;

#if (MED_MAJOR_NUM == 3)
  med_idt fid = MEDfileOpen(fileName.c_str(), MED_ACC_RDONLY);
#else
  med_idt fid = MEDouvrir((char*)fileName.c_str(), MED_LECTURE);
#endif
  if(fid < 0) {
    Msg::Error("Unable to open file '%s'", fileName.c_str());
    return fieldNames;
  }

#if (MED_MAJOR_NUM == 3)
  med_int numFields = MEDnField(fid);
#else
  med_int numFields = MEDnChamp(fid, 0);
#endif

  for(int index = 0; index < numFields; index++){

    med_int numComp = MEDnChamp(fid, index + 1);
    if(numComp <= 0){
      Msg::Error("Could not get number of components for MED field");
      return fieldNames;
    }

    char name[MED_TAILLE_NOM + 1], meshName[MED_TAILLE_NOM + 1];
    char dtUnit[MED_TAILLE_PNOM + 1];
    std::vector<char> compName(numComp * MED_TAILLE_PNOM + 1);
    std::vector<char> compUnit(numComp * MED_TAILLE_PNOM + 1);
    med_int numSteps = 0;
    med_type_champ type;
#if (MED_MAJOR_NUM == 3)
    med_bool localMesh;
    if(MEDfieldInfo(fid, index + 1, name, meshName, &localMesh, &type,
                    &compName[0], &compUnit[0], dtUnit, &numSteps) < 0){
#else
    if(MEDchampInfo(fid, index + 1, name, &type, &compName[0], &compUnit[0],
                    numComp) < 0){
#endif
      Msg::Error("Could not get MED field info");
      return fieldNames;
    }
    fieldNames.push_back(name);
  }

#if (MED_MAJOR_NUM == 3)
  if(MEDfileClose(fid) < 0){
#else
  if(MEDfermer(fid) < 0){
#endif
    Msg::Error("Unable to close file '%s'", fileName.c_str());
  }
  return fieldNames;
}

bool PViewDataGModel::readMED(const std::string &fileName, int fileIndex)
{
  med_idt fid = MEDouvrir((char*)fileName.c_str(), MED_LECTURE);
  if(fid < 0){
    Msg::Error("Unable to open file '%s'", fileName.c_str());
    return false;
  }

  med_int numComp = MEDnChamp(fid, fileIndex + 1);
  if(numComp <= 0){
    Msg::Error("Could not get number of components for MED field");
    return false;
  }

  char name[MED_TAILLE_NOM + 1], meshName[MED_TAILLE_NOM + 1];
  char dtUnit[MED_TAILLE_PNOM + 1];
  std::vector<char> compName(numComp * MED_TAILLE_PNOM + 1);
  std::vector<char> compUnit(numComp * MED_TAILLE_PNOM + 1);
  med_int numSteps = 0;
  med_type_champ type;
#if (MED_MAJOR_NUM == 3)
  med_bool localMesh;
  if(MEDfieldInfo(fid, fileIndex + 1, name, meshName, &localMesh, &type,
                  &compName[0], &compUnit[0], dtUnit, &numSteps) < 0){
#else
  if(MEDchampInfo(fid, fileIndex + 1, name, &type, &compName[0], &compUnit[0],
                  numComp) < 0){
#endif
    Msg::Error("Could not get MED field info");
    return false;
  }

  Msg::Info("Reading %d-component field <<%s>>", numComp, name);
  setName(name);
  setFileName(fileName);
  setFileIndex(fileIndex);

  int numCompMsh =
    (numComp <= 1) ? 1 : (numComp <= 3) ? 3 : (numComp <= 9) ? 9 : numComp;

  if(numCompMsh > 9)
    Msg::Warning("More than 9 components in field: you will probably want to force "
                 "the field type to scalar, vector or tensor in the options");

  // Warning! The ordering of the elements in the last two lists is
  // important: it should match the ordering of the MSH element types
  // (when elements are saved without tags, this governs the order
  // with which we implicitly index them in GModel::readMED)
  const med_entite_maillage entType[] =
    {MED_NOEUD, MED_MAILLE, MED_NOEUD_MAILLE};
#if (MED_MAJOR_NUM == 3)
  const med_geometrie_element eleType[] =
    {MED_NONE, MED_SEG2, MED_TRIA3, MED_QUAD4, MED_TETRA4, MED_HEXA8,
     MED_PENTA6, MED_PYRA5, MED_SEG3, MED_TRIA6, MED_QUAD9, MED_TETRA10,
     MED_HEXA27, MED_POINT1, MED_QUAD8, MED_HEXA20, MED_PENTA15, MED_PYRA13};
  const int nodesPerEle[] =
    {0, 2, 3, 4, 4, 8, 6, 5, 3, 6, 9, 10, 27, 1, 8, 20, 15, 13};
#else
  const med_geometrie_element eleType[] =
    {MED_NONE, MED_SEG2, MED_TRIA3, MED_QUAD4, MED_TETRA4, MED_HEXA8,
     MED_PENTA6, MED_PYRA5, MED_SEG3, MED_TRIA6, MED_TETRA10,
     MED_POINT1, MED_QUAD8, MED_HEXA20, MED_PENTA15, MED_PYRA13};
  const int nodesPerEle[] =
    {0, 2, 3, 4, 4, 8, 6, 5, 3, 6, 10, 1, 8, 20, 15, 13};
#endif

  std::vector<std::pair<int, int> > pairs;
  for(unsigned int i = 0; i < sizeof(entType) / sizeof(entType[0]); i++){
    for(unsigned int j = 0; j < sizeof(eleType) / sizeof(eleType[0]); j++){
      if((!i && !j) || j){
#if (MED_MAJOR_NUM == 3)
        med_int n = numSteps;
#else
        med_int n = MEDnPasdetemps(fid, name, entType[i], eleType[j]);
#endif
        if(n > 0){
          pairs.push_back(std::pair<int, int>(i, j));
          numSteps = std::max(numSteps, n);
        }
        if(!i && !j) break; // MED_NOEUD does not care about eleType
      }
    }
  }

  if(numSteps < 1 || pairs.empty()){
    Msg::Error("Nothing to import from MED file");
    return false;
  }

  for(int step = 0; step < numSteps; step++){

    // FIXME: in MED3 we might want to loop over all profiles instead
    // of relying of the default one

    // FIXME: MED3 allows to store multi-step meshes; we should
    // interface this with our own gmodel-per-step structure

    for(unsigned int pair = 0; pair < pairs.size(); pair++){
      // get step info
      med_entite_maillage ent = entType[pairs[pair].first];
      med_geometrie_element ele = eleType[pairs[pair].second];
      med_int numdt, numit, ngauss;
      med_float dt;
#if (MED_MAJOR_NUM == 3)
      if(MEDfieldComputingStepInfo(fid, name, step + 1, &numdt, &numit, &dt) < 0){
#else
      char dtunit[MED_TAILLE_PNOM + 1];
      med_booleen local;
      med_int numMeshes;
      if(MEDpasdetempsInfo(fid, name, ent, ele, step + 1, &ngauss, &numdt, &numit,
                           dtunit, &dt, meshName, &local, &numMeshes) < 0){
#endif
        Msg::Error("Could not read step info");
        return false;
      }
      // create step data
      if(!pair){
        GModel *m = GModel::findByName(meshName);
        if(!m){
          Msg::Error("Could not find mesh <<%s>>", meshName);
          return false;
        }
        while(step >= (int)_steps.size())
          _steps.push_back(new stepData<double>(m, numCompMsh));
        _steps[step]->fillEntities();
        _steps[step]->computeBoundingBox();
        _steps[step]->setFileName(fileName);
        _steps[step]->setFileIndex(fileIndex);
        _steps[step]->setTime(dt);
      }

      char locName[MED_TAILLE_NOM + 1], profileName[MED_TAILLE_NOM + 1];

      // get number of values in the field (numVal takes the number of
      // Gauss points or the number of nodes per element into account,
      // but not the number of components)
#if (MED_MAJOR_NUM == 3)
      med_int profileSize;
      med_int numVal = MEDfieldnValueWithProfile(fid, name, numdt, numit, ent, ele,
                                                 1, MED_COMPACT_STMODE, profileName,
                                                 &profileSize, locName, &ngauss);
      numVal *= ngauss;
#else
      med_int numVal = MEDnVal(fid, name, ent, ele, numdt, numit, meshName,
                               MED_COMPACT);
#endif
      if(numVal <= 0) continue;

      _type = (ent == MED_NOEUD) ? NodeData : (ent == MED_MAILLE) ?
        ElementData : ElementNodeData;
      int mult = 1;
      if(ent == MED_NOEUD_MAILLE){
        mult = nodesPerEle[pairs[pair].second];
      }
      else if(ngauss != 1){
        mult = ngauss;
        _type = GaussPointData;
      }
      _steps[step]->resizeData(numVal / mult);

      // read field data
      std::vector<double> val(numVal * numComp);
#if (MED_MAJOR_NUM == 3)
      if(MEDfieldValueWithProfileRd(fid, name, numdt, numit, ent, ele, MED_COMPACT_STMODE,
                                    profileName, MED_FULL_INTERLACE, MED_ALL_CONSTITUENT,
                                    (unsigned char*)&val[0]) < 0){
#else
      if(MEDchampLire(fid, meshName, name, (unsigned char*)&val[0], MED_FULL_INTERLACE,
                      MED_ALL, locName, profileName, MED_COMPACT, ent, ele,
                      numdt, numit) < 0){
#endif
        Msg::Error("Could not read field values");
        return false;
      }

      Msg::Debug("MED: eletyp=%d entity=%d (0:cell, 3:node, 4:elenode) ngauss=%d "
                 "localizationName=%s profileName=%s -- stepDataType=%d",
                 ele, ent, ngauss, locName, profileName, _type);

      // read Gauss point data
      if(_type == GaussPointData){
        std::vector<double> &p(_steps[step]->getGaussPoints(med2mshElementType(ele)));
        if(std::string(locName) == MED_GAUSS_ELNO){
          // special case: the gauss points are the vertices of the
          // element; in this case no explicit localization has to be
          // created in MED
          p.resize(ngauss * 3, 1.e22);
        }
        else{
          int dim = ele / 100;
          std::vector<med_float> refcoo((ele % 100) * dim);
          std::vector<med_float> gscoo(ngauss * dim);
          std::vector<med_float> wg(ngauss);
#if (MED_MAJOR_NUM == 3)
          if(MEDlocalizationRd(fid, locName, MED_FULL_INTERLACE, &refcoo[0],
                               &gscoo[0], &wg[0]) < 0){
#else
          if(MEDgaussLire(fid, &refcoo[0], &gscoo[0], &wg[0], MED_FULL_INTERLACE,
                          locName) < 0){
#endif
            Msg::Error("Could not read Gauss points");
            return false;
          }
          // FIXME: we should check that refcoo corresponds to our
          // internal reference element
          for(int i = 0; i < (int)gscoo.size(); i++){
            p.push_back(gscoo[i]);
            if(i % dim == dim - 1) for(int j = 0; j < 3 - dim; j++) p.push_back(0.);
          }
        }
      }

      // compute profile (indices in full array of entities of given type)
      std::vector<med_int> profile;
      if(std::string(profileName) != MED_NOPFL){
        med_int n = MEDnValProfil(fid, profileName);
        if(n > 0){
          Msg::Debug("MED has full profile");
          profile.resize(n);
#if (MED_MAJOR_NUM == 3)
          if(MEDprofileRd(fid, profileName, &profile[0]) < 0){
#else
          if(MEDprofilLire(fid, &profile[0], profileName) < 0){
#endif
            Msg::Error("Could not read profile");
            return false;
          }
        }
      }
      if(profile.empty()){
        Msg::Debug("MED profile is empty -- using continuous sequence");
        profile.resize(numVal / mult);
        for(unsigned int i = 0; i < profile.size(); i++)
          profile[i] = i + 1;
      }

      // get size of full array and tags (if any) of entities
      bool nodal = (ent == MED_NOEUD);
#if (MED_MAJOR_NUM == 3)
      med_bool changeOfCoord;
      med_bool geoTransform;
      med_int numEnt = MEDmeshnEntity(fid, meshName, MED_NO_DT, MED_NO_IT,
                                      nodal ? MED_NODE : MED_CELL,
                                      nodal ? MED_NO_GEOTYPE : ele,
                                      nodal ? MED_COORDINATE : MED_CONNECTIVITY,
                                      nodal ? MED_NO_CMODE : MED_NODAL,
                                      &changeOfCoord, &geoTransform);
#else
      med_int numEnt = MEDnEntMaa(fid, meshName, nodal ? MED_COOR : MED_CONN,
                                  nodal ? MED_NOEUD : MED_MAILLE,
                                  nodal ? MED_NONE : ele,
                                  nodal ? (med_connectivite)0 : MED_NOD);
#endif
      std::vector<med_int> tags(numEnt);
#if (MED_MAJOR_NUM == 3)
      if(MEDmeshEntityNumberRd(fid, meshName, MED_NO_DT, MED_NO_IT,
                               nodal ? MED_NODE : MED_CELL,
                               nodal ? MED_NO_GEOTYPE : ele, &tags[0]) < 0)
#else
      if(MEDnumLire(fid, meshName, &tags[0], numEnt, nodal ? MED_NOEUD : MED_MAILLE,
                    nodal ? MED_NONE : ele) < 0)
#endif
        tags.clear();

      // if we don't have tags, compute the starting index (i.e., how many
      // elements of different type are in the mesh before these ones)
      int startIndex = 0;
      if(tags.empty()){
        int maxv, maxe;
        _steps[step]->getModel()->getCheckPointedMaxNumbers(maxv, maxe);
        if(nodal){
          startIndex += maxv;
        }
        else{
          for(int i = 1; i < pairs[pair].second; i++){
#if (MED_MAJOR_NUM == 3)
            med_int n = MEDmeshnEntity(fid, meshName, MED_NO_DT, MED_NO_IT,
                                       MED_CELL, eleType[i], MED_CONNECTIVITY,
                                       MED_NODAL, &changeOfCoord, &geoTransform);
#else
            med_int n = MEDnEntMaa(fid, meshName, MED_CONN, MED_MAILLE,
                                   eleType[i], MED_NOD);
#endif
            if(n > 0) startIndex += n;
          }
          startIndex += maxe;
        }
        Msg::Debug("MED has no tags -- assuming starting index %d", startIndex);
      }

      // compute entity numbers using profile, then fill step data
      for(unsigned int i = 0; i < profile.size(); i++){
        int num;
        if(tags.empty()){
          num = startIndex + profile[i];
        }
        else{
          if(profile[i] == 0 || profile[i] > (int)tags.size()){
            Msg::Error("Wrong index in profile");
            return false;
          }
          num = tags[profile[i] - 1];
        }

        double *d = _steps[step]->getData(num, true, mult);
        for(int j = 0; j < mult; j++){
          // reorder nodes if we have ElementNode data
          int j2 = (ent == MED_NOEUD_MAILLE) ? med2mshNodeIndex(ele, j) : j;
          for(int k = 0; k < numComp; k++)
            d[numCompMsh * j + k] = val[numComp * mult * i + numComp * j2 + k];
        }
      }
    }
  }

  finalize();

  if(MEDfermer(fid) < 0){
    Msg::Error("Unable to close file '%s'", (char*)fileName.c_str());
    return false;
  }
  return true;
}

bool PViewDataGModel::writeMED(const std::string &fileName)
{
  if(_steps.empty()) return true;

  if(hasMultipleMeshes()){
    Msg::Error("Export not done for multi-mesh views");
    return false;
  }

  if(_type != NodeData){
    Msg::Error("Can only export node-based datasets for now");
    return false;
  }

  GModel *model = _steps[0]->getModel();

  // save the mesh
  if(!model->writeMED(fileName, true)) return false;

  std::string meshName(model->getName());
  std::string fieldName(getName());

  med_idt fid = MEDouvrir((char*)fileName.c_str(), MED_LECTURE_AJOUT);
  if(fid < 0){
    Msg::Error("Unable to open file '%s'", fileName.c_str());
    return false;
  }

  // compute profile
  char *profileName = (char*)"nodeProfile";
  std::vector<med_int> profile, indices;
  for(int i = 0; i < _steps[0]->getNumData(); i++){
    if(_steps[0]->getData(i)){
      MVertex *v = _steps[0]->getModel()->getMeshVertexByTag(i);
      if(!v){
        Msg::Error("Unknown vertex %d in data", i);
        return false;
      }
      profile.push_back(v->getIndex());
      indices.push_back(i);
    }
  }

  if(profile.empty()){
    Msg::Error("Nothing to save");
    return false;
  }

#if (MED_MAJOR_NUM == 3)
  if(MEDprofileWr(fid, profileName, (med_int)profile.size(), &profile[0]) < 0){
#else
  if(MEDprofilEcr(fid, &profile[0], (med_int)profile.size(), profileName) < 0){
#endif
    Msg::Error("Could not create MED profile");
    return false;
  }

  int numComp = _steps[0]->getNumComponents();
#if (MED_MAJOR_NUM == 3)
  if(MEDfieldCr(fid, (char*)fieldName.c_str(), MED_FLOAT64, (med_int)numComp,
                "unknown", "unknown", "unknown", (char*)meshName.c_str()) < 0){
#else
  if(MEDchampCr(fid, (char*)fieldName.c_str(), MED_FLOAT64,
                (char*)"unknown", (char*)"unknown",
                (med_int)numComp) < 0){
#endif
    Msg::Error("Could not create MED field");
    return false;
  }

#if (MED_MAJOR_NUM == 3)
  med_bool changeOfCoord, geoTransform;
  med_int numNodes = MEDmeshnEntity(fid, (char*)meshName.c_str(),
                                    MED_NO_DT, MED_NO_IT, MED_NODE,
                                    MED_NO_GEOTYPE, MED_COORDINATE, MED_NO_CMODE,
                                    &changeOfCoord, &geoTransform);
#else
  med_int numNodes = MEDnEntMaa(fid, (char*)meshName.c_str(), MED_COOR, MED_NOEUD,
                                MED_NONE, (med_connectivite)0);
#endif
  if(numNodes <= 0){
    Msg::Error("Could not get valid number of nodes in mesh");
    return false;
  }
  for(unsigned int step = 0; step < _steps.size(); step++){
    unsigned int n = 0;
    for(int i = 0; i < _steps[step]->getNumData(); i++)
      if(_steps[step]->getData(i)) n++;
    if(n != profile.size() || numComp != _steps[step]->getNumComponents()){
      Msg::Error("Skipping incompatible step");
      continue;
    }
    double time = _steps[step]->getTime();
    std::vector<double> val(profile.size() * numComp);
    for(unsigned int i = 0; i < profile.size(); i++)
      for(int k = 0; k < numComp; k++)
        val[i * numComp + k] = _steps[step]->getData(indices[i])[k];
#if (MED_MAJOR_NUM == 3)
    if(MEDfieldValueWithProfileWr(fid, (char*)fieldName.c_str(), (med_int)(step + 1),
                                  MED_NO_IT,
                                  time, MED_NODE, MED_NO_GEOTYPE, MED_COMPACT_STMODE,
                                  profileName, "", MED_FULL_INTERLACE,
                                  MED_ALL_CONSTITUENT, numNodes,
                                  (unsigned char*)&val[0]) < 0){
#else
    if(MEDchampEcr(fid, (char*)meshName.c_str(), (char*)fieldName.c_str(),
                   (unsigned char*)&val[0],
                   MED_FULL_INTERLACE, numNodes, (char*)MED_NOGAUSS, MED_ALL,
                   profileName, MED_COMPACT, MED_NOEUD, MED_NONE, (med_int)step,
                   (char*)"unknown", time, MED_NONOR) < 0){
#endif
      Msg::Error("Could not write MED field");
      return false;
    }
  }

  if(MEDfermer(fid) < 0){
    Msg::Error("Unable to close file '%s'", (char*)fileName.c_str());
    return false;
  }
  return true;
}

#else

bool PViewDataGModel::readMED(const std::string &fileName, int fileIndex)
{
  Msg::Error("Gmsh must be compiled with MED support to read '%s'",
             fileName.c_str());
  return false;
}

bool PViewDataGModel::writeMED(const std::string &fileName)
{
  Msg::Error("Gmsh must be compiled with MED support to write '%s'",
             fileName.c_str());
  return false;
}

#endif