mcnp2cad.cpp

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#include <iostream>
#include <fstream>
#include <string>
#include <stdexcept>
#include <cctype>
#include <vector>
#include <set>
#include <map>
#include <sstream>
#include <algorithm>

#include <cassert>

#include "iGeom.h"
#include "geometry.hpp"
#include "MCNPInput.hpp"
#include "options.hpp"
#include "volumes.hpp"
#include "ProgOptions.hpp"
#include "version.hpp"


/* mcnp2cad should be compatible with any implementation of the iGeom library.
 * But when we know that CGM is the implementation of iGeom that we're using,
 * we can do a few other useful things.  Those extra things are confined to this
 * file and guarded by this macro.
 */
//#ifdef USING_CGMA

#include <RefEntityFactory.hpp>
#include <Body.hpp>
#include <GeometryQueryTool.hpp>
#include <CubitMessage.hpp>


static bool CGMA_opt_inhibit_intersect_errs = false;

/*  CubitMessage doesn't provide a way to shut up error messages.
 *  For those rare cases when we really want that behavior, we set up 
 *  a message handler that just drops messages.
 */
class SilentCubitMessageHandler : public CubitMessageHandler
{

public:
  static int num_dropped_errors;

  SilentCubitMessageHandler() {}

  virtual void print_message_prefix(const char *){}
  virtual void print_message(const char *){}
  virtual void print_error_prefix(const char *){}
  virtual void print_error(const char *){num_dropped_errors++;}
};

int SilentCubitMessageHandler::num_dropped_errors = 0;

/* RAII class to set up and shut down a SilentCubitMessageHandler */
class CubitSilence
{
protected:
  CubitMessageHandler* old_handler;
  SilentCubitMessageHandler silencer;
public:
  CubitSilence() :
    old_handler( CubitMessage::instance()->get_message_handler() )
  {
    CubitMessage::instance()->set_message_handler( &silencer );
  }

  ~CubitSilence(){
    CubitMessage::instance()->set_message_handler( old_handler );
  }
};

//#endif /* USING_CGMA */

typedef std::vector<iBase_EntityHandle> entity_collection_t;

// intersect two volumes that may or may not overlap; return true on success.
static bool intersectIfPossible( iGeom_Instance igm, 
                                 iBase_EntityHandle h1, iBase_EntityHandle h2, iBase_EntityHandle* result, 
                                 bool delete_on_failure = true)
{
  int igm_result;

//#ifdef USING_CGMA
  if( CGMA_opt_inhibit_intersect_errs ){
    CubitSilence s;
    iGeom_intersectEnts( igm, h1, h2, result, &igm_result); 
  }  else
//#endif
  {
    iGeom_intersectEnts( igm, h1, h2, result, &igm_result);
  }
  
  if( igm_result == iBase_SUCCESS ){
    return true;
  }
  else{
    if( delete_on_failure ){
      iGeom_deleteEnt( igm, h1, &igm_result);
      CHECK_IGEOM(igm_result, "deleting an intersection candidate");
      iGeom_deleteEnt( igm, h2, &igm_result);
      CHECK_IGEOM(igm_result, "deleting an intersection candidate");
    }
    return false;
  }
}

// determine whether the bounding boxes of two volumes overlap.
// this can save an expensive call to intersectIfPossible()
static bool boundBoxesIntersect( iGeom_Instance igm, iBase_EntityHandle h1, iBase_EntityHandle h2 ){

  Vector3d h1_min, h1_max, h2_min, h2_max;
  int igm_result;
  
  iGeom_getEntBoundBox( igm, h1, h1_min.v, h1_min.v+1, h1_min.v+2, h1_max.v, h1_max.v+1, h1_max.v+2, &igm_result );
  CHECK_IGEOM( igm_result, "Getting bounding box h1" );
  iGeom_getEntBoundBox( igm, h2, h2_min.v, h2_min.v+1, h2_min.v+2, h2_max.v, h2_max.v+1, h2_max.v+2, &igm_result );
  CHECK_IGEOM( igm_result, "Getting bounding box h2" );

  bool ret = false;

  for( int i = 0; i < 3 && ret == false; ++i ){
    ret = ret || ( h1_min.v[i] > h2_max.v[i] );
    ret = ret || ( h2_min.v[i] > h1_max.v[i] );
  }

  return !ret;

}

class GeometryContext {

protected:

  // note: this appears slow, since it's called for all cells and constructs a string
  // for each.  A lookup table would probably be faster, but there are never more than
  // a few thousand cells.
  std::string materialName( int mat, double rho ){
    std::string ret;
    std::stringstream formatter;
    if(Gopt.uwuw_names){
      bool mass_density = false;
      if (rho <= 0){
        mass_density = true;
        rho = -rho;
      }
      char rho_formatted [50];
      sprintf(rho_formatted, "%E", rho);
      formatter << "mat:m" << mat;
      if(mass_density)
          formatter << "/rho:" <<rho_formatted;
      else
          formatter << "/atom:" << rho_formatted;
    }
    else
      formatter << "mat_" << mat << "_rho_" << rho;
    formatter >> ret;
    return ret;
  }

  std::string importanceName( char impchar, double imp ){
    std::string ret; 
    std::stringstream formatter;
    formatter << "imp." << impchar << "_" << imp;
    formatter >> ret;
    return ret;
  }

  class NamedGroup {
  protected:
    std::string name;
    entity_collection_t entities;
  public:
    NamedGroup( ) : name("") {}
    NamedGroup( std::string name_p ):
      name(name_p)
    {}

    const std::string& getName() const { return name; }
    const entity_collection_t& getEntities() const { return entities; }

    void add( iBase_EntityHandle new_handle ){
      entities.push_back(new_handle);
    }

    void update( iBase_EntityHandle old_h, iBase_EntityHandle new_h ){
      entity_collection_t::iterator i = std::find( entities.begin(), entities.end(), old_h );
      if( i != entities.end() ){
        if( new_h ){
          *i = new_h;
        }
        else {
          entities.erase( i );
        }
      }
    }

    bool contains( iBase_EntityHandle handle ) const {
      return std::find( entities.begin(), entities.end(), handle ) != entities.end(); 
    }

  };

  class NamedEntity { 
  protected:
    iBase_EntityHandle handle;
    std::string name;
  public:
    NamedEntity( iBase_EntityHandle handle_p, std::string name_p = "" ):
      handle(handle_p), name(name_p)
    {}
    virtual ~NamedEntity(){}

    const std::string& getName() const { return name; }
    iBase_EntityHandle getHandle() const{ return handle; }

    void setHandle( iBase_EntityHandle new_h ) {
      handle = new_h;
    }

    static NamedEntity* makeCellIDName( iBase_EntityHandle h, int ident ){
      NamedEntity* e = new NamedEntity(h);
      std::stringstream formatter;
      formatter << "MCNP_ID_" << ident;
      formatter >> e->name;
      return e;
    }

  };

protected:
  iGeom_Instance& igm;
  InputDeck& deck;
  double world_size;
  int universe_depth;

  std::map< std::string, NamedGroup* > named_groups;
  std::vector< NamedEntity* > named_cells;

  NamedGroup* getNamedGroup( const std::string& name ){
    if( named_groups.find( name ) == named_groups.end() ){
      named_groups[ name ] = new NamedGroup( name );
      if( OPT_DEBUG ) std::cout << "New named group: " << name 
                                << "num groups now " << named_groups.size() << std::endl;
    }
    return named_groups[ name ];
  }

public:
  GeometryContext( iGeom_Instance& igm_p, InputDeck& deck_p ) :
    igm(igm_p), deck(deck_p), world_size(0.0), universe_depth(0)
  {}

  bool defineLatticeNode( CellCard& cell, iBase_EntityHandle cell_shell, iBase_EntityHandle lattice_shell,
                          int x, int y, int z, entity_collection_t& accum );
  

  entity_collection_t defineCell( CellCard& cell, bool defineEmbedded, iBase_EntityHandle lattice_shell );
  entity_collection_t populateCell( CellCard& cell, iBase_EntityHandle cell_shell, iBase_EntityHandle lattice_shell );
 

  entity_collection_t defineUniverse( int universe, iBase_EntityHandle container, const Transform* transform );
  

  void addToVolumeGroup( iBase_EntityHandle cell, const std::string& groupname );
  void setVolumeCellID( iBase_EntityHandle cell, int ident);
  void setMaterial( iBase_EntityHandle cell, int material, double density ){
    if( Gopt.tag_materials ){
        addToVolumeGroup( cell, materialName(material,density) );
    }
  }

  void setImportances( iBase_EntityHandle cell, const std::map<char, double>& imps ){
    if( Gopt.tag_importances ){
      for( std::map<char, double>::const_iterator i = imps.begin();
           i != imps.end(); ++i )
      {
          char impchar = (*i).first;
          double imp = (*i).second;
          addToVolumeGroup( cell, importanceName( impchar, imp ) );
      }
    }
  }


  void updateMaps ( iBase_EntityHandle old_cell, iBase_EntityHandle new_cell );

  bool mapSanityCheck( iBase_EntityHandle* cells, size_t count );

  void tagGroups( );
  void tagCellIDsAsEntNames();

  std::string uprefix() { 
    return std::string( universe_depth, ' ' );
  }

  iBase_EntityHandle createGraveyard( iBase_EntityHandle& boundary );
  void createGeometry( );

};

void GeometryContext::addToVolumeGroup( iBase_EntityHandle cell, const std::string& name ){

  NamedGroup* group = getNamedGroup( name );
  group->add( cell );

  if( OPT_DEBUG ){ std::cout << uprefix() 
                             << "Added cell to volgroup " << group->getName() << std::endl; }
}


void GeometryContext::setVolumeCellID( iBase_EntityHandle cell, int ident ){

  named_cells.push_back( NamedEntity::makeCellIDName(cell, ident) );

}

void GeometryContext::updateMaps( iBase_EntityHandle old_cell, iBase_EntityHandle new_cell ){

  /* update named_groups.  handling of new_cell == NULL case is performed within NamedGroup class */
  for( std::map<std::string,NamedGroup*>::iterator i = named_groups.begin();
       i != named_groups.end(); ++i )
  {
    NamedGroup* group = (*i).second;
    group->update( old_cell, new_cell );
  }

  /* update named entities.*/
  if( new_cell != NULL ){
    for( std::vector< NamedEntity* >::iterator i = named_cells.begin(); 
         i != named_cells.end(); ++i )
      {
        NamedEntity* ne = *i;
        if( ne->getHandle() == old_cell ){
          ne->setHandle( new_cell );
        }
      }
  }
  else{ /* new_cell == NULL (i.e. cell has disappeared) */

    // this case is expected to be uncommon in most geometries, so the fact that erasing
    // from a std::vector is slow should not be a problem.
    std::vector< NamedEntity* >::iterator i = named_cells.begin();
    while( i != named_cells.end() ){
      if( (*i)->getHandle() == old_cell ){
        delete (*i);
        named_cells.erase(i);
      }
      else{
        ++i;
      }
    }
  }

}

void GeometryContext::tagGroups( ){

  // the NamedGroup system used to be used solely to create groups for material specification,
  // but it has since been expanded for importance groups.  Some of the old messages that
  // talk about material groups could be confusing.
  int igm_result;
  
  std::string name_tag_id = "NAME";
  int name_tag_maxlength = 64;
  iBase_TagHandle name_tag;

  iGeom_getTagHandle( igm, name_tag_id.c_str(), &name_tag, &igm_result, name_tag_id.length() );
  CHECK_IGEOM( igm_result, "Looking up NAME tag" );
  
  iGeom_getTagSizeBytes( igm, name_tag, &name_tag_maxlength, &igm_result );
  CHECK_IGEOM( igm_result, "Querying NAME tag length" );
  if( OPT_DEBUG ) std::cout << "Name tag length: " << name_tag_maxlength << " actual id " << name_tag << std::endl;

  for( std::map<std::string,NamedGroup*>::iterator i = named_groups.begin(); i != named_groups.end(); ++i ){

    NamedGroup* group = (*i).second;
    if(OPT_VERBOSE){ 
      std::cout << "Creating volume group " << group->getName() << " of size " << group->getEntities().size() << std::endl;
    }

    iBase_EntitySetHandle set;
    iGeom_createEntSet( igm, 0, &set, &igm_result );
    CHECK_IGEOM( igm_result, "Creating a new entity set " );
    
    const entity_collection_t& group_list = group->getEntities();
    for( entity_collection_t::const_iterator j = group_list.begin(); j != group_list.end(); ++j ){
      iGeom_addEntToSet( igm, *j, set, &igm_result );
      CHECK_IGEOM( igm_result, "Adding entity to material set" );
    }

    std::string name = group->getName();
    if( name.length() > (unsigned)name_tag_maxlength ){
      name.resize( name_tag_maxlength - 1);
      std::cerr << "Warning: trimmed material name " << group->getName() 
                << " to length " << name_tag_maxlength << std::endl;
    }

    iGeom_setEntSetData( igm, set, name_tag, name.c_str(), name.length(), &igm_result );
    CHECK_IGEOM( igm_result, "Naming a material group's EntitySet" );
    
  }

}

void GeometryContext::tagCellIDsAsEntNames(){
  
  int igm_result;

  std::string name_tag_id = "NAME";
  int name_tag_maxlength = 64;
  iBase_TagHandle name_tag;

  iGeom_getTagHandle( igm, name_tag_id.c_str(), &name_tag, &igm_result, name_tag_id.length() );
  CHECK_IGEOM( igm_result, "Looking up NAME tag" );
  
  iGeom_getTagSizeBytes( igm, name_tag, &name_tag_maxlength, &igm_result );
  CHECK_IGEOM( igm_result, "Querying NAME tag length" );
  if( OPT_DEBUG ) std::cout << "Name tag length: " << name_tag_maxlength << " actual id " << name_tag << std::endl;


  if( OPT_VERBOSE ){ std::cout << "Naming " << named_cells.size() << " volumes." <<  std::endl; }

  for( std::vector< NamedEntity* >::iterator i = named_cells.begin(); i!=named_cells.end(); ++i){
    std::string name = (*i)->getName();
    iBase_EntityHandle entity = (*i)->getHandle();

    if( name.length() > (unsigned)name_tag_maxlength ){
      name.resize( name_tag_maxlength - 1);
      std::cerr << "Warning: trimmed entity name " << (*i)->getName() 
                << " to length " << name_tag_maxlength << std::endl;
    }

    if( entity == NULL ){ std::cerr << "Error: NULL in named_cells" << std::endl; continue; }
    
    iGeom_setData( igm, entity, name_tag, name.c_str(), name.length(), &igm_result );
    CHECK_IGEOM( igm_result, "Naming an NamedEntity" );
  }

}

bool GeometryContext::mapSanityCheck( iBase_EntityHandle* cells, size_t count){ 
  bool good = true;
  int igm_result;

  iBase_EntitySetHandle rootset;
  iGeom_getRootSet( igm, &rootset, &igm_result );
  CHECK_IGEOM( igm_result, "Getting root set for sanity check" );

  int num_regions;
  iGeom_getNumOfType( igm, rootset, iBase_REGION, &num_regions, &igm_result );
  CHECK_IGEOM( igm_result, "Getting num regions for sanity check" );

  iBase_EntityHandle * handle_vector = new iBase_EntityHandle[ num_regions ];
  int size = 0;

  std::cout << "Map sanity check: num_regions = " << num_regions << std::endl;
  iGeom_getEntities( igm, rootset, iBase_REGION, &handle_vector, &num_regions, &size, &igm_result );
  CHECK_IGEOM( igm_result, "Getting entities for sanity check" );

  std::cout << "Map sanity check: root set size = " << size << " (" << num_regions << ")" << std::endl;
  std::cout << "Cell count: " << count << std::endl;
  
  // sanity conditions: all the entityhandles in the naming lists are part of the cells list
  std::set< iBase_EntityHandle > allRegions;
  for( size_t i = 0; i < count; ++i ){
    allRegions.insert( cells[i] );
  }
  
  int named_group_volume_count = 0;
  for( std::map<std::string, NamedGroup*>::iterator i = named_groups.begin(); i!=named_groups.end(); ++i){
    NamedGroup* group = (*i).second;
    named_group_volume_count += group->getEntities().size();

    // graveyard cells are not present in allRegions
    if( group->getName() == "graveyard" )
      continue;

    entity_collection_t group_cells = group->getEntities();
    
    for( entity_collection_t::iterator j = group_cells.begin(); j != group_cells.end(); ++j ){
      bool check = allRegions.find( *j ) != allRegions.end();
      if( ! check ){
        std::cout << "Entity handle " << *j << " is not in allRegions!" << std::endl;
      }
      good = good && check;
    }
  }

  std::cout << "Num EntityHandles in NamedGroups: " << named_group_volume_count << std::endl;

  if( good ){ std::cout << "Map sanity check: pass!"  << std::endl; }
  else{ std::cout << "WARNING: Failed map sanity check!" << std::endl; }

  return good;
}

bool GeometryContext::defineLatticeNode(  CellCard& cell, iBase_EntityHandle cell_shell, iBase_EntityHandle lattice_shell,
                                          int x, int y, int z, entity_collection_t& accum )
{
  const Lattice& lattice = cell.getLattice();
  int lattice_universe =   cell.getUniverse();

  const FillNode* fn = &(lattice.getFillForNode( x, y, z ));                            
  Transform t = lattice.getTxForNode( x, y, z );        
  int igm_result;
  
  iBase_EntityHandle cell_copy;
  iGeom_copyEnt( igm, cell_shell, &cell_copy, &igm_result );
  CHECK_IGEOM( igm_result, "Copying a lattice cell shell" );
  cell_copy = applyTransform( t, igm, cell_copy );
  
  if( !boundBoxesIntersect( igm, cell_copy, lattice_shell ) ){
    iGeom_deleteEnt( igm, cell_copy, &igm_result);
    CHECK_IGEOM( igm_result, "Deleting a lattice cell shell" );
    if( OPT_DEBUG ) std::cout << uprefix() << " node failed bbox check" << std::endl;
    return false;
  }

  entity_collection_t node_subcells;
  if( fn->getFillingUniverse() == 0 ){
    // this node of the lattice was assigned universe zero, meaning it's
    // defined to be emtpy. Delete the shell and return true.
    iGeom_deleteEnt( igm, cell_copy, &igm_result );
    CHECK_IGEOM( igm_result, "Deleting a universe-0 lattice cell" );
    return true;
  }
  else if( fn->getFillingUniverse() == lattice_universe ){
    // this node is just a translated copy of the origin element in the lattice
    setVolumeCellID(cell_copy, cell.getIdent());
    if( cell.getMat() != 0 ){ setMaterial( cell_copy, cell.getMat(), cell.getRho() ); }
    if( cell.getImportances().size() ){ setImportances( cell_copy, cell.getImportances()); }
    node_subcells.push_back( cell_copy );
  }
  else{
    // this node has an embedded universe

    iBase_EntityHandle cell_copy_unmoved;
    iGeom_copyEnt( igm, cell_shell, &cell_copy_unmoved, &igm_result );
    CHECK_IGEOM( igm_result, "Re-copying a lattice cell shell" );
    node_subcells = defineUniverse(  fn->getFillingUniverse(), cell_copy_unmoved, (fn->hasTransform() ? &(fn->getTransform()) : NULL ) );
    for( size_t i = 0; i < node_subcells.size(); ++i ){
      node_subcells[i] = applyTransform( t, igm, node_subcells[i] );
    }

    iGeom_deleteEnt( igm, cell_copy, &igm_result );
    CHECK_IGEOM( igm_result, "Deleting lattice cell copy" );

  }

  // bound the node with the enclosing lattice shell
  bool success = false;
  for( size_t i = 0; i < node_subcells.size(); ++i ){
    iBase_EntityHandle lattice_shell_copy;
    iGeom_copyEnt( igm, lattice_shell, &lattice_shell_copy, &igm_result );

    iBase_EntityHandle result;
    if( intersectIfPossible( igm, lattice_shell_copy, node_subcells[i], &result, true ) ){
      updateMaps( node_subcells[i], result );
      if( OPT_DEBUG ) std::cout << " node defined successfully" << std::endl;
      accum.push_back( result );
      success = true;
    }
    else{ 
      // lattice_shell_copy and node_subcells[i] were deleted by intersectIfPossible(),
      // so there's no need to delete them explicitly
      updateMaps( node_subcells[i], NULL );
      if( OPT_DEBUG ) std::cout << " node failed intersection" << std::endl;
    }
  }

  return success;
}

typedef struct{ int v[3]; } int_triple;

static std::vector<int_triple> makeGridShellOfRadius( int r, int dimensions ){
  if( r == 0 ){ 
    int_triple v; v.v[0] = v.v[1] = v.v[2] = 0;
    return std::vector<int_triple>(1,v);
  }
  else{
    std::vector<int_triple> ret;
    
    int jmin = dimensions > 1 ? -r : 0;
    int jmax = dimensions > 1 ?  r : 0;
    int kmin = dimensions > 2 ? -r : 0;
    int kmax = dimensions > 2 ?  r : 0;
    for( int i = -r; i <= r; ++i ){
      for( int j = jmin;j <= jmax; ++j ){
        for( int k = kmin; k <= kmax; ++k ){
          if( i == -r || i == r ||
              j == -r || j == r ||
              k == -r || k == r ){
            int_triple v;
            v.v[0] = i; 
            v.v[1] = j;
            v.v[2] = k;
            ret.push_back(v);
          }
        }
      }
    }
    return ret;
  }
}

entity_collection_t GeometryContext::populateCell( CellCard& cell,  iBase_EntityHandle cell_shell, 
                                                   iBase_EntityHandle lattice_shell = NULL )
{
  
  if( OPT_DEBUG ) std::cout << uprefix() << "Populating cell " << cell.getIdent() << std::endl;


  if( !cell.hasFill() && !cell.isLattice() ){
    // no further geometry inside this cell; set its material
    setVolumeCellID(cell_shell, cell.getIdent());
    if( cell.getMat() != 0 ){ setMaterial( cell_shell, cell.getMat(), cell.getRho() ); }
    if( cell.getImportances().size() ){ setImportances( cell_shell, cell.getImportances()); }
    return entity_collection_t(1, cell_shell );
  }
  else if(cell.hasFill() && !cell.isLattice()){
    // define a simple (non-lattice) fill
    
    const FillNode& n = cell.getFill().getOriginNode();
    int filling_universe = n.getFillingUniverse();
    
    if( OPT_DEBUG ){
      std::cout << uprefix() << "Creating cell " << cell.getIdent() 
                << ", which is filled with universe " << filling_universe << std::endl;
    }
    
    // the contained universe is transformed by the FillNode's transform, if any, or
    // else by the cell's TRCL value, if any.
    const Transform* t;
    if( n.hasTransform() ){
      t = &(n.getTransform());
    } else if( cell.getTrcl().hasData() ){
      t = &(cell.getTrcl().getData() );
    } else { 
      t = NULL; 
    }

    if( OPT_DEBUG && t ) std::cout << uprefix() << " ... and has transform: " << *t << std::endl;

    entity_collection_t subcells = defineUniverse(  filling_universe, cell_shell, t );
 
    return subcells;
     
  }
  else {
    // cell is a lattice, bounded by lattice_shell.  cell_shell is the origin element of the lattice and
    // cell->getLattice() has the lattice parameters.

    assert(lattice_shell);
    
    if( OPT_VERBOSE ) std::cout << uprefix() << "Creating cell " << cell.getIdent() << "'s lattice" << std::endl;

    entity_collection_t subcells;
        
    const Lattice& lattice = cell.getLattice();
    int num_dims = lattice.numFiniteDirections();
    
    if( OPT_DEBUG ) std::cout << uprefix() << "  lattice num dims: " << num_dims << std::endl;

    if( lattice.isFixedSize() ){

      if( OPT_DEBUG ) std::cout << uprefix() << "Defining fixed lattice" << std::endl;

      irange xrange = lattice.getXRange(), yrange = lattice.getYRange(), zrange = lattice.getZRange();

      for( int i = xrange.first; i <= xrange.second; ++i){
        for( int j = yrange.first; j <= yrange.second; ++j ){
          for( int k = zrange.first; k <= zrange.second; ++k ){

            if( OPT_DEBUG ) std::cout << uprefix() << "Defining lattice node " << i << ", " << j << ", " << k << std::endl;

            /* bool success = */ defineLatticeNode( cell, cell_shell, lattice_shell, i, j, k, subcells );

            if( num_dims < 3 ) break; // from z loop
          }
          if( num_dims < 2 ) break; // from y loop
        }
      }

    }
    else{

      if( OPT_DEBUG ) std::cout << uprefix() << "Defining infinite lattice" << std::endl;
      if( OPT_VERBOSE && Gopt.infinite_lattice_extra_effort ) 
        std::cout << uprefix() << "Infinite lattice extra effort enabled." << std::endl;

      // when extra effort is enabled, initialize done_one to false;
      // the code will keep trying to create lattice elements until at least one 
      // element has been successfully created.
      bool done = false, done_one = !Gopt.infinite_lattice_extra_effort;
      int radius = 0;

      while( !done ){
        
        done = done_one;
        std::vector<int_triple> shell = makeGridShellOfRadius(radius++, num_dims);

        for( std::vector<int_triple>::iterator i = shell.begin(); i!=shell.end(); ++i){
          int x = (*i).v[0];
          int y = (*i).v[1];
          int z = (*i).v[2];
          
          if( OPT_DEBUG ) std::cout << uprefix() << "Defining lattice node " << x << ", " << y << ", " << z << std::endl;

          bool success = defineLatticeNode( cell, cell_shell, lattice_shell, x, y, z, subcells );
          if( success ){
            done = false;
            done_one = true;
          }

        }       
      }
    }

    int igm_result;
    iGeom_deleteEnt( igm, cell_shell, &igm_result );
    CHECK_IGEOM( igm_result, "Deleting cell shell after building lattice" );
    iGeom_deleteEnt( igm, lattice_shell, &igm_result );
    CHECK_IGEOM( igm_result, "Deleting lattice shell after building lattice" );

    return subcells;
  }
}

entity_collection_t GeometryContext::defineCell(  CellCard& cell,  bool defineEmbedded = true, 
                                                  iBase_EntityHandle lattice_shell = NULL )
{
  int ident = cell.getIdent();
  const CellCard::geom_list_t& geom = cell.getGeom();
 
  if( OPT_VERBOSE ) std::cout << uprefix() << "Defining cell " << ident << std::endl;

  int igm_result;

  entity_collection_t tmp;

  std::vector<iBase_EntityHandle> stack;
  for(CellCard::geom_list_t::const_iterator i = geom.begin(); i!=geom.end(); ++i){
    
    const CellCard::geom_list_entry_t& token = (*i);
    switch(token.first){
    case CellCard::CELLNUM:
      // a cell number appears in a geometry list only because it is being complemented with the # operator
      // thus, when defineCell is called on it, set defineEmbedded to false
      tmp = defineCell( *(deck.lookup_cell_card(token.second)), false);
      assert(tmp.size() == 1);
      stack.push_back( tmp.at(0) );
      break;
    case CellCard::SURFNUM:
      {      
        int surface = token.second;
        bool pos = true;
        if( surface < 0){
          pos = false; surface = -surface;
        }
        try{
          SurfaceVolume& surf = makeSurface( deck.lookup_surface_card( surface ) );
          iBase_EntityHandle surf_handle = surf.define( pos, igm, world_size );
          stack.push_back(surf_handle);
        }
        catch(std::runtime_error& e) { std::cerr << e.what() << std::endl; }
      }
      break;
    case CellCard::MBODYFACET:
      {
        int cellnum = std::abs(token.second) / 10;
        int facet = std::abs(token.second) - (cellnum*10);
        std::cerr << "Attempting to define facet " << facet << " of cell " << cellnum << std::endl;
        throw std::runtime_error( "Macrobody facets are not yet supported by mcnp2cad." );
      }
      break;
    case CellCard::INTERSECT:
      {
        assert( stack.size() >= 2 );
        iBase_EntityHandle s1 = stack.back(); stack.pop_back();
        iBase_EntityHandle s2 = stack.back(); stack.pop_back();
        iBase_EntityHandle result;
        if( intersectIfPossible( igm, s1, s2, &result ) ){
          stack.push_back(result);
        }
        else{
          std::cout << "FAILED INTERSECTION CELL #" << cell.getIdent() << std::endl;
          throw std::runtime_error("Intersection failed");
        }
      }
      break;
    case CellCard::UNION:
      { 
        assert( stack.size() >= 2 );
        iBase_EntityHandle s[2];
        s[0] = stack.back(); stack.pop_back();
        s[1] = stack.back(); stack.pop_back();
        iBase_EntityHandle result;
        iGeom_uniteEnts( igm, s, 2, &result, &igm_result);
        CHECK_IGEOM( igm_result, "Uniting two entities" );
        stack.push_back(result);
      }
      break;
    case CellCard::COMPLEMENT:
      {
        assert (stack.size() >= 1 );
        iBase_EntityHandle world_sphere = makeWorldSphere(igm, world_size);
        iBase_EntityHandle s = stack.back(); stack.pop_back();
        iBase_EntityHandle result;

        iGeom_subtractEnts( igm, world_sphere, s, &result, &igm_result);
        CHECK_IGEOM( igm_result, "Complementing an entity" );
        stack.push_back(result);
      }
      break;
    default:
      throw std::runtime_error( "Unexpected token while evaluating cell geometry");
      break;
    }
  }

  assert( stack.size() == 1);

  iBase_EntityHandle cellHandle = stack[0];

  if( cell.getTrcl().hasData() ){
    cellHandle = applyTransform( cell.getTrcl().getData(), igm, cellHandle );
  }

  if( defineEmbedded ){
    return populateCell( cell, cellHandle, lattice_shell );
  }
  else{
    return entity_collection_t( 1, cellHandle );
  }
  
}

entity_collection_t GeometryContext::defineUniverse( int universe, iBase_EntityHandle container = NULL, 
                                                     const Transform* transform = NULL )
{

  if( OPT_VERBOSE ) std::cout << uprefix() << "Defining universe " << universe << std::endl;
  universe_depth++;

  InputDeck::cell_card_list u_cells = deck.getCellsOfUniverse( universe );
  entity_collection_t subcells;

  iBase_EntityHandle lattice_shell = NULL;
  if( u_cells.size() == 1 && u_cells[0]->isLattice() ){
    lattice_shell = container;
    // reverse-transform the containing volume before using it as a lattice boundary
    if(transform){
      lattice_shell = applyReverseTransform( *transform, igm, lattice_shell );
    }
  }

  // define all the cells of this universe
  for( InputDeck::cell_card_list::iterator i = u_cells.begin(); i!=u_cells.end(); ++i){
    entity_collection_t tmp = defineCell( *(*i), true, lattice_shell );
    for( size_t i = 0; i < tmp.size(); ++i){
      subcells.push_back( tmp[i] );
    }
  }
  
  if( transform ){
    for( size_t i = 0; i < subcells.size(); ++i){
      subcells[i] = applyTransform( *transform, igm, subcells[i] );      
    }
  }

  if( container && !lattice_shell ){
    
    int igm_result;
    
    for( size_t i = 0; i < subcells.size(); ++i ){
      
      if( OPT_DEBUG ) std::cout << uprefix() << "Bounding a universe cell..." << std::flush;    
      bool subcell_removed = false;

      if( boundBoxesIntersect( igm, subcells[i], container )){
        iBase_EntityHandle container_copy;
        iGeom_copyEnt( igm, container, &container_copy, &igm_result);
        CHECK_IGEOM( igm_result, "Copying a universe-bounding cell" );
        
        iBase_EntityHandle subcell_bounded;
        bool valid_result = intersectIfPossible( igm, container_copy, subcells[i], &subcell_bounded );
        if( valid_result ){
          updateMaps( subcells[i], subcell_bounded );
          subcells[i] = subcell_bounded;
          if( OPT_DEBUG ) std::cout << " ok." <<  std::endl;
        }
        else{
          subcell_removed = true;
        }

      }
      else{
        // bounding boxes didn't intersect, delete subcells[i].
        // this suggests invalid geometry, but we can continue anyway.
        iGeom_deleteEnt( igm, subcells[i], &igm_result );
        CHECK_IGEOM( igm_result, "Deleting a subcell that didn't intersect a parent's bounding box (strange!)" );
        subcell_removed = true;
      }
      
      if( subcell_removed ){
        updateMaps( subcells[i], NULL );
        subcells.erase( subcells.begin()+i );
        i--;
        if( OPT_DEBUG ) std::cout << " removed." << std::endl;
      }
      
    }
        
    iGeom_deleteEnt( igm, container, &igm_result );
    CHECK_IGEOM( igm_result, "Deleting a bounding cell" );
  }

  universe_depth--;
  if( OPT_VERBOSE ) std::cout << uprefix() << "Done defining universe " << universe << std::endl;

  return subcells;
 
}

iBase_EntityHandle GeometryContext::createGraveyard( iBase_EntityHandle& inner_copy ) {
  iBase_EntityHandle inner, outer, graveyard;
  int igm_result;

#ifdef CGM_HAVE_FACET_ENGINE_ONLY
  FacetModifyEngine::set_modify_enabled(CUBIT_TRUE);
#endif

  double inner_size = 2.0 * world_size;
  iGeom_createBrick( igm, inner_size, inner_size, inner_size, &inner, &igm_result );
  CHECK_IGEOM( igm_result, "Making graveyard" );
  
  iGeom_copyEnt( igm, inner, &inner_copy, &igm_result );
  CHECK_IGEOM( igm_result, "Copying graveyard" );
  
  double outer_size = 2.0 * ( world_size + (world_size / 50.0) );
  iGeom_createBrick( igm, outer_size, outer_size, outer_size, &outer, &igm_result );
  CHECK_IGEOM( igm_result, "Making outer graveyard" );

  iGeom_subtractEnts( igm, outer, inner, &graveyard, &igm_result );
  CHECK_IGEOM( igm_result, "subtracting graveyard" );
  
  addToVolumeGroup( graveyard, "graveyard" );
  
  // reset world size to a sphere that bounds the inner shell of this graveyard
  world_size *= sqrt(3.0);
  if( OPT_DEBUG ) std::cout << "Spherical world size for graveyard: " << world_size << std::endl;
  
  return graveyard;

}

void GeometryContext::createGeometry( ){

  int igm_result;
 
  InputDeck::cell_card_list    cells     = deck.getCells();
  InputDeck::surface_card_list surfaces  = deck.getSurfaces();
  InputDeck::data_card_list    datacards = deck.getDataCards();

  // estimate how large the geometry will need to be to accomodate all the surfaces
  for( InputDeck::surface_card_list::iterator i = surfaces.begin(); i!=surfaces.end(); ++i){
    // catch all exceptions from makeSurface at this time; if they exist, they will
    // more properly be displayed to the user at a later time.  Right now we just want
    // to estimate a size and failures can be ignored.
    try{
      world_size = std::max( world_size, makeSurface( *i ).getFarthestExtentFromOrigin() );
    } catch(std::runtime_error& e){}
  }

  // translations can extend the size of the world
  double translation_addition = 0;
  for( InputDeck::data_card_list::iterator i = datacards.begin(); i!=datacards.end(); ++i){
    DataCard* c = *i;
    if( c->getKind() == DataCard::TR ){
      double tform_len = dynamic_cast<DataRef<Transform>*>(c)->getData().getTranslation().length();
      translation_addition = std::max (translation_addition, tform_len );
    }
  }

  for( InputDeck::cell_card_list::iterator i = cells.begin(); i!=cells.end(); ++i){
    CellCard* c = *i;
      // translations can come from TRCL data
    if( c->getTrcl().hasData() ){
      double tform_len = c->getTrcl().getData().getTranslation().length();
      translation_addition = std::max( translation_addition, tform_len );
    }
    // translations can also come from fill nodes.  This implementation does *not* take
    // lattices into account, as they are assumed to be contained within other volumes.
    if( c->hasFill() && c->getFill().getOriginNode().hasTransform() ){
      double tform_len = c->getFill().getOriginNode().getTransform().getTranslation().length();
      translation_addition = std::max( translation_addition, tform_len );
    }
  }

  world_size += translation_addition;
  world_size *= 1.2;

  std::cout << "World size: " << world_size << " (trs added " << translation_addition << ")" << std::endl;

  iBase_EntityHandle graveyard = NULL, graveyard_boundary = NULL;
  if( Gopt.make_graveyard ){
    graveyard = createGraveyard ( graveyard_boundary ); 
  }

  std::cout << "Defining geometry..." << std::endl;

  entity_collection_t defined_cells = defineUniverse( 0, graveyard_boundary );
  if( graveyard ){ defined_cells.push_back(graveyard); }

  size_t count = defined_cells.size();
  iBase_EntityHandle *cell_array = new iBase_EntityHandle[ count ];
  for( unsigned int i = 0; i < count; ++i ){
    cell_array[i] = defined_cells[i];
  }

//#ifdef USING_CGMA
  {
    // in CGM's default implementation, each new volume and surface created
    // through CSG operations gets a new unique ID number, so those IDs can
    // be large and widely-spaced.  We want them to start from 1.
    RefEntityFactory::instance()->compress_ref_ids("surface", false );
    RefEntityFactory::instance()->compress_ref_ids("volume", false );
  }
//#endif


  if( OPT_DEBUG ){ mapSanityCheck(cell_array, count); }
  tagGroups();

  if( Gopt.tag_cell_IDs ){
    tagCellIDsAsEntNames();
  }
  

  if ( Gopt.imprint_geom ) {
    std::cout << "Imprinting all...\t\t\t" << std::flush;
    iGeom_imprintEnts( igm, cell_array, count, &igm_result );
    CHECK_IGEOM( igm_result, "Imprinting all cells" );
    std::cout << " done." << std::endl;
    
    double tolerance = world_size / 1.0e7;
    if( Gopt.override_tolerance ){
      tolerance = Gopt.specific_tolerance;
    }

    if ( Gopt.merge_geom ) {
      std::cout << "Merging, tolerance=" << tolerance << "...\t\t" << std::flush;
      iGeom_mergeEnts( igm, cell_array, count,  tolerance, &igm_result );
      CHECK_IGEOM( igm_result, "Merging all cells" );
      std::cout << " done." << std::endl;
    }
  }


  std::string outName = Gopt.output_file;
  std::cout << "Saving file \"" << outName << "\"...\t\t\t" << std::flush;
  iGeom_save( igm, outName.c_str(), "", &igm_result, outName.length(), 0 );
  CHECK_IGEOM( igm_result, "saving the output file "+outName );
  std::cout << " done." << std::endl;

}

void debugSurfaceDistances( InputDeck& deck, std::ostream& out = std::cout ){

  InputDeck::surface_card_list& surfaces = deck.getSurfaces();
  for( InputDeck::surface_card_list::iterator i = surfaces.begin(); i!=surfaces.end(); ++i){
    try{
      const SurfaceVolume& s = makeSurface(*i);
      out << "S" << (*i)->getIdent() << " distance from origin: " << s.getFarthestExtentFromOrigin() << std::endl;
    }
    catch(std::runtime_error& e){
      std::cerr << "Error debugging surface distances: " << e.what() << std::endl;
      throw;
    }
  }
  
}

std::string mcnp2cad_version(bool full = true);


struct program_option_struct Gopt;

int main(int argc, char* argv[]){

  // set default options
  Gopt.verbose = Gopt.debug = false;
  Gopt.infinite_lattice_extra_effort = false;
  Gopt.tag_materials = true;
  Gopt.tag_importances = true;
  Gopt.tag_cell_IDs = true;
  Gopt.make_graveyard = true;
  Gopt.imprint_geom = true;
  Gopt.merge_geom = true;
  Gopt.input_file = "";
  Gopt.output_file = OPT_DEFAULT_OUTPUT_FILENAME;
  Gopt.igeom_init_options = "";
  Gopt.override_tolerance = false;
  Gopt.uwuw_names = false;

  bool DiFlag = false, DoFlag = false;

  ProgOptions po("mcnp2cad " + mcnp2cad_version(false) +  ": An MCNP geometry to CAD file converter");
  po.setVersion( mcnp2cad_version() );

  po.addOpt<void>("extra-effort,e","Use extra effort to get infinite lattices right (may be slow)", 
                  &Gopt.infinite_lattice_extra_effort );
  po.addOpt<void>("verbose,v", "Verbose output", &Gopt.verbose );
  po.addOpt<void>("debug,D", "Debugging (very verbose) output", &Gopt.debug );
  po.addOpt<void>("Di", "Debug output for MCNP parsing phase only", &DiFlag);
  po.addOpt<void>("Do","Debug output for iGeom output phase only", &DoFlag);

  po.addOptionHelpHeading( "Options controlling CAD output:" );
  po.addOpt<std::string>(",o", "Give name of output file. Default: " + Gopt.output_file, &Gopt.output_file );
  po.addOpt<double>("tol,t", "Specify a tolerance for merging surfaces", &Gopt.specific_tolerance );
  po.addOpt<void>("skip-mats,M", "Do not tag materials using group names", 
                  &Gopt.tag_materials, po.store_false );
  po.addOpt<void>("skip-imps,P", "Do not tag cell importances using group names",
                  &Gopt.tag_importances, po.store_false );
  po.addOpt<void>("skip-nums,N", "Do not tag cell numbers using body names",
                  &Gopt.tag_cell_IDs, po.store_false );
  po.addOpt<void>("skip-merge,E", "Do not merge the geometry",
                  &Gopt.merge_geom, po.store_false );
  po.addOpt<void>("skip-imprint,I", "Do not imprint the geometry; implies skip-merge",
                  &Gopt.imprint_geom, po.store_false );
  po.addOpt<void>("skip-graveyard,G", "Do not bound the geometry with a `graveyard' bounding box",
                  &Gopt.make_graveyard, po.store_false );
  po.addOpt<void>("uwuw-names,U", "Use a UWUW compatible name scheme for material groups,"
                                   "i.e. 'mat:mX/rho:Y' where X is material number is Y is density",
                  &Gopt.uwuw_names, po.store_true );

//#ifdef USING_CGMA
  po.addOptionHelpHeading ("Options controlling CGM library:");
  po.addOpt<int>("geomver","Override geometry export engine version");
  po.addOptionHelpHeading ("    (use --geomver 1600 for backward compatibility w/ Cubit 10.2)");
  po.addOpt<void>("Cv", "Verbose messages from CGM" );
  po.addOpt<void>("Cq", "Silence warning messages from CGM" );
  po.addOpt<void>("CIq","Silence ERROR messages from CGM when doing intersect tests.");
  po.addOptionHelpHeading( "         (May be useful for infinite lattices, but use cautiously)" );
//#endif

  po.addRequiredArg( "input_file", "Path to MCNP geometry input file", &Gopt.input_file );

  po.parseCommandLine( argc, argv );

  if( po.numOptSet( "tol,t" ) ){
    Gopt.override_tolerance = true;
    if( Gopt.specific_tolerance <= 0.0 || Gopt.specific_tolerance > .1 ){
      std::cerr << "Warning: you seem to have specified an unusual tolerance (" 
                << Gopt.specific_tolerance << ")." << std::endl;
    }
  }

//#ifdef USING_CGMA

  // Enable the info_flag only if --Cv is requested
  if(po.numOptSet( "Cv" )){
    CubitMessage::instance()->set_info_flag( true );
  }
  else{
    CubitMessage::instance()->set_info_flag( false );
  }

  // Silence warnings if --Cq is set
  if(po.numOptSet( "Cq" )){    
    CubitMessage::instance()->set_warning_flag( false );
  }

  // Enable silent intersection errors if --CIq is set
  if(po.numOptSet( "CIq" )){
    CGMA_opt_inhibit_intersect_errs = true;
  }

//#endif

  if( Gopt.merge_geom && !Gopt.imprint_geom ) {
    std::cerr << "Warning: cannot merge geometry without imprinting, will skip merge too." << std::endl;
  }

  std::ifstream input(Gopt.input_file.c_str(), std::ios::in );
  if( !input.is_open() ){
    std::cerr << "Error: couldn't open file \"" << Gopt.input_file << "\"" << std::endl;
    return 1;
  }
  
  std::cout << "Reading input file..." << std::endl;

  // if --Di and not -D, set debugging to be true for InputDeck::build() call only
  if( DiFlag && !OPT_DEBUG){
    Gopt.debug = true;
  }
  else{ DiFlag = false; }

  InputDeck& deck = InputDeck::build(input);
  std::cout << "Done reading input." << std::endl;

  // turn off debug if it was set by --Di only
  if( DiFlag ){ Gopt.debug = false; }
  
  if( DoFlag && !OPT_DEBUG ){ Gopt.debug = true; }

  if( OPT_DEBUG ){ 
    debugSurfaceDistances( deck );
  }

#ifdef CGM_HAVE_FACET_ENGINE_ONLY
  FacetModifyEngine::set_modify_enabled(CUBIT_TRUE);
#endif

  iGeom_Instance igm;
  int igm_result; 

  iGeom_newGeom( Gopt.igeom_init_options.c_str(), &igm, &igm_result, Gopt.igeom_init_options.length() );
  CHECK_IGEOM( igm_result, "Initializing iGeom");

//#ifdef USING_CGMA
  int export_vers;
  if( po.getOpt( "geomver", &export_vers) ){
    if( CUBIT_SUCCESS == GeometryQueryTool::instance()->set_export_allint_version( export_vers ) ){
      std::cout << "Set export engine version to " << export_vers << std::endl; 
    }
    // on failure, an error message will be printed by CGM
  }

//#endif

  GeometryContext context( igm, deck );
  context.createGeometry();
  
//#ifdef USING_CGMA
  if( CGMA_opt_inhibit_intersect_errs && SilentCubitMessageHandler::num_dropped_errors > 0){
    std::cout << "--CIq: supressed " << SilentCubitMessageHandler::num_dropped_errors << " intersection errors." << std::endl;
  }
//#endif 

  return 0;
}

std::string mcnp2cad_version( bool full ){
  std::stringstream str;
  str << (full ? "mcnp2cad version " : "")
      << MCNP2CAD_VERSION_MAJOR << "." 
      << MCNP2CAD_VERSION_MINOR << "." 
      << MCNP2CAD_VERSION_REV;
  if(full)
      str << "\nCompiled on " << __DATE__ << " at " << __TIME__ ;
  return str.str();
}