smesh/src/StdMeshers/StdMeshers_Regular_1D.cxx

//  SMESH SMESH : implementaion of SMESH idl descriptions
//
//  Copyright (C) 2003  OPEN CASCADE, EADS/CCR, LIP6, CEA/DEN,
//  CEDRAT, EDF R&D, LEG, PRINCIPIA R&D, BUREAU VERITAS 
// 
//  This library is free software; you can redistribute it and/or 
//  modify it under the terms of the GNU Lesser General Public 
//  License as published by the Free Software Foundation; either 
//  version 2.1 of the License. 
// 
//  This library is distributed in the hope that it will be useful, 
//  but WITHOUT ANY WARRANTY; without even the implied warranty of 
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
//  Lesser General Public License for more details. 
// 
//  You should have received a copy of the GNU Lesser General Public 
//  License along with this library; if not, write to the Free Software 
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA 
// 
//  See http://www.opencascade.org/SALOME/ or email : webmaster.salome@opencascade.org 
//
//
//
//  File   : StdMeshers_Regular_1D.cxx
//           Moved here from SMESH_Regular_1D.cxx
//  Author : Paul RASCLE, EDF
//  Module : SMESH
//  $Header$

using namespace std;

#include "StdMeshers_Regular_1D.hxx"
#include "SMESH_Gen.hxx"
#include "SMESH_Mesh.hxx"

#include "StdMeshers_LocalLength.hxx"
#include "StdMeshers_NumberOfSegments.hxx"
#include "StdMeshers_Arithmetic1D.hxx"
#include "StdMeshers_StartEndLength.hxx"
#include "StdMeshers_Deflection1D.hxx"
#include <StdMeshers_AutomaticLength.hxx>

#include "SMDS_MeshElement.hxx"
#include "SMDS_MeshNode.hxx"
#include "SMDS_EdgePosition.hxx"
#include "SMESH_subMesh.hxx"

#include "Utils_SALOME_Exception.hxx"
#include "utilities.h"

#include <BRep_Tool.hxx>
#include <TopoDS_Edge.hxx>
#include <TopoDS_Shape.hxx>
#include <TopTools_ListIteratorOfListOfShape.hxx>
#include <GeomAdaptor_Curve.hxx>
#include <GCPnts_AbscissaPoint.hxx>
#include <GCPnts_UniformAbscissa.hxx>
#include <GCPnts_UniformDeflection.hxx>
#include <Standard_ErrorHandler.hxx>
#include <Precision.hxx>
#include <Expr_GeneralExpression.hxx>
#include <Expr_NamedUnknown.hxx>
#include <Expr_Array1OfNamedUnknown.hxx>
#include <TColStd_Array1OfReal.hxx>
#include <ExprIntrp_GenExp.hxx>

#include <CASCatch_CatchSignals.hxx>
#include <CASCatch_Failure.hxx> 
#include <CASCatch_ErrorHandler.hxx>
#include <OSD.hxx>
#include <math_GaussSingleIntegration.hxx>

#include <string>
#include <math.h>

//=============================================================================
/*!
 *  
 */
//=============================================================================

StdMeshers_Regular_1D::StdMeshers_Regular_1D(int hypId, int studyId,
	SMESH_Gen * gen):SMESH_1D_Algo(hypId, studyId, gen)
{
	MESSAGE("StdMeshers_Regular_1D::StdMeshers_Regular_1D");
	_name = "Regular_1D";
	_shapeType = (1 << TopAbs_EDGE);

	_compatibleHypothesis.push_back("LocalLength");
	_compatibleHypothesis.push_back("NumberOfSegments");
	_compatibleHypothesis.push_back("StartEndLength");
	_compatibleHypothesis.push_back("Deflection1D");
	_compatibleHypothesis.push_back("Arithmetic1D");
	_compatibleHypothesis.push_back("AutomaticLength");
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

StdMeshers_Regular_1D::~StdMeshers_Regular_1D()
{
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

bool StdMeshers_Regular_1D::CheckHypothesis
                         (SMESH_Mesh& aMesh,
                          const TopoDS_Shape& aShape,
                          SMESH_Hypothesis::Hypothesis_Status& aStatus)
{
  _hypType = NONE;

  const list <const SMESHDS_Hypothesis * >&hyps = GetUsedHypothesis(aMesh, aShape);
  if (hyps.size() == 0)
  {
    aStatus = SMESH_Hypothesis::HYP_MISSING;
    return false;  // can't work without a hypothesis
  }

  // use only the first hypothesis
  const SMESHDS_Hypothesis *theHyp = hyps.front();

  string hypName = theHyp->GetName();

  if (hypName == "LocalLength")
  {
    const StdMeshers_LocalLength * hyp =
      dynamic_cast <const StdMeshers_LocalLength * >(theHyp);
    ASSERT(hyp);
    _value[ BEG_LENGTH_IND ] = _value[ END_LENGTH_IND ] = hyp->GetLength();
    ASSERT( _value[ BEG_LENGTH_IND ] > 0 );
    _hypType = LOCAL_LENGTH;
    aStatus = SMESH_Hypothesis::HYP_OK;
  }

  else if (hypName == "NumberOfSegments")
  {
    const StdMeshers_NumberOfSegments * hyp =
      dynamic_cast <const StdMeshers_NumberOfSegments * >(theHyp);
    ASSERT(hyp);
    _ivalue[ NB_SEGMENTS_IND  ] = hyp->GetNumberOfSegments();
    ASSERT( _ivalue[ NB_SEGMENTS_IND ] > 0 );
    _ivalue[ DISTR_TYPE_IND ] = (int) hyp->GetDistrType();
    switch (_ivalue[ DISTR_TYPE_IND ])
    {
    case StdMeshers_NumberOfSegments::DT_Scale:
      _value[ SCALE_FACTOR_IND ] = hyp->GetScaleFactor();
      break;
    case StdMeshers_NumberOfSegments::DT_TabFunc:
      _vvalue[ TAB_FUNC_IND ] = hyp->GetTableFunction();
      break;
    case StdMeshers_NumberOfSegments::DT_ExprFunc:
      _svalue[ EXPR_FUNC_IND ] = hyp->GetExpressionFunction();
      break;
    case StdMeshers_NumberOfSegments::DT_Regular:
      break;
    default:
      ASSERT(0);
      break;
    }
    if (_ivalue[ DISTR_TYPE_IND ] == StdMeshers_NumberOfSegments::DT_TabFunc ||
        _ivalue[ DISTR_TYPE_IND ] == StdMeshers_NumberOfSegments::DT_ExprFunc)
      _ivalue[ EXP_MODE_IND ] = (int) hyp->IsExponentMode();
    _hypType = NB_SEGMENTS;
    aStatus = SMESH_Hypothesis::HYP_OK;
  }

  else if (hypName == "Arithmetic1D")
  {
    const StdMeshers_Arithmetic1D * hyp =
      dynamic_cast <const StdMeshers_Arithmetic1D * >(theHyp);
    ASSERT(hyp);
    _value[ BEG_LENGTH_IND ] = hyp->GetLength( true );
    _value[ END_LENGTH_IND ] = hyp->GetLength( false );
    ASSERT( _value[ BEG_LENGTH_IND ] > 0 && _value[ END_LENGTH_IND ] > 0 );
    _hypType = ARITHMETIC_1D;
    aStatus = SMESH_Hypothesis::HYP_OK;
  }

  else if (hypName == "StartEndLength")
  {
    const StdMeshers_StartEndLength * hyp =
      dynamic_cast <const StdMeshers_StartEndLength * >(theHyp);
    ASSERT(hyp);
    _value[ BEG_LENGTH_IND ] = hyp->GetLength( true );
    _value[ END_LENGTH_IND ] = hyp->GetLength( false );
    ASSERT( _value[ BEG_LENGTH_IND ] > 0 && _value[ END_LENGTH_IND ] > 0 );
    _hypType = BEG_END_LENGTH;
    aStatus = SMESH_Hypothesis::HYP_OK;
  }

  else if (hypName == "Deflection1D")
  {
    const StdMeshers_Deflection1D * hyp =
      dynamic_cast <const StdMeshers_Deflection1D * >(theHyp);
    ASSERT(hyp);
    _value[ DEFLECTION_IND ] = hyp->GetDeflection();
    ASSERT( _value[ DEFLECTION_IND ] > 0 );
    _hypType = DEFLECTION;
    aStatus = SMESH_Hypothesis::HYP_OK;
  }

  else if (hypName == "AutomaticLength")
  {
    StdMeshers_AutomaticLength * hyp = const_cast<StdMeshers_AutomaticLength *>
      (dynamic_cast <const StdMeshers_AutomaticLength * >(theHyp));
    ASSERT(hyp);
    _value[ BEG_LENGTH_IND ] = _value[ END_LENGTH_IND ] = hyp->GetLength( &aMesh, aShape );
    ASSERT( _value[ BEG_LENGTH_IND ] > 0 );
    _hypType = LOCAL_LENGTH;
    aStatus = SMESH_Hypothesis::HYP_OK;
  }
  else
    aStatus = SMESH_Hypothesis::HYP_INCOMPATIBLE;

  return ( _hypType != NONE );
}

//=======================================================================
//function : compensateError
//purpose  : adjust theParams so that the last segment length == an
//=======================================================================

static void compensateError(double a1, double an,
                            double U1, double Un,
                            double             length,
                            GeomAdaptor_Curve& C3d,
                            list<double> &     theParams)
{
  int i, nPar = theParams.size();
  if ( a1 + an < length && nPar > 1 )
  {
    list<double>::reverse_iterator itU = theParams.rbegin();
    double Ul = *itU++;
    // dist from the last point to the edge end <Un>, it should be equal <an>
    double Ln = GCPnts_AbscissaPoint::Length( C3d, Ul, Un );
    double dLn = an - Ln; // error of <an>
    if ( Abs( dLn ) <= Precision::Confusion() )
      return;
    double dU = Abs( Ul - *itU ); // parametric length of the last but one segment
    double dUn = dLn * Abs( Un - U1 ) / length; // parametric error of <an>
    if ( dUn < 0.5 * dU ) { // last segment is a bit shorter than it should
      dUn = -dUn; // move the last parameter to the edge beginning
    }
    else {  // last segment is much shorter than it should -> remove the last param and
      theParams.pop_back(); nPar--; // move the rest points toward the edge end
      Ln = GCPnts_AbscissaPoint::Length( C3d, theParams.back(), Un );
      dUn = ( an - Ln ) * Abs( Un - U1 ) / length;
      if ( dUn < 0.5 * dU )
        dUn = -dUn;
    }
    if ( U1 > Un )
      dUn = -dUn;
    double q  = dUn / ( nPar - 1 );
    for ( itU = theParams.rbegin(), i = 1; i < nPar; itU++, i++ ) {
      (*itU) += dUn;
      dUn -= q;
    }
  }
}

class Function 
{
public:
  Function( const bool exp )
  : myExp( exp )
  {
  }

  virtual ~Function()
  {
  }

  virtual bool   value( const double, double& f )
  {
    if( myExp )
      f = pow( 10, f );
    return true;
  }
  virtual double integral( const double, const double ) = 0;

private:
  bool myExp;
};

class FunctionIntegral : public Function
{
public:
  FunctionIntegral( Function*, const double );
  virtual ~FunctionIntegral();
  virtual bool   value( const double, double& );
  virtual double integral( const double, const double );

private:
  Function* myFunc;
  double    myStart;
};

FunctionIntegral::FunctionIntegral( Function* f, const double st )
: Function( false )
{
  myFunc = f;
  myStart = st;
}

FunctionIntegral::~FunctionIntegral()
{
}

bool FunctionIntegral::value( const double t, double& f )
{
  f = myFunc ? myFunc->integral( myStart, t ) : 0;
  return myFunc!=0 && Function::value( t, f );
}

double FunctionIntegral::integral( const double, const double )
{
  return 0;
}

class FunctionTable : public Function
{
public:
  FunctionTable( const std::vector<double>&, const bool );
  virtual ~FunctionTable();
  virtual bool   value( const double, double& );
  virtual double integral( const double, const double );

private:
  bool    findBounds( const double, int&, int& ) const;

  //integral from x[i] to x[i+1]
  double  integral( const int i );

  //integral from x[i] to x[i]+d
  //warning: function is presented as linear on interaval from x[i] to x[i]+d,
  //         for correct result d must be >=0 and <=x[i+1]-x[i]
  double  integral( const int i, const double d );

private:
  std::vector<double>  myData;
};

FunctionTable::FunctionTable( const std::vector<double>& data, const bool exp )
: Function( exp )
{
  myData = data;
}

FunctionTable::~FunctionTable()
{
}

bool FunctionTable::value( const double t, double& f )
{
  int i1, i2;
  if( !findBounds( t, i1, i2 ) )
    return false;

  double
    x1 = myData[2*i1], y1 = myData[2*i1+1],
    x2 = myData[2*i2], y2 = myData[2*i2+1];

  Function::value( x1, y1 );
  Function::value( x2, y2 );
  
  f = y1 + ( y2-y1 ) * ( t-x1 ) / ( x2-x1 );
  return true;
}

double FunctionTable::integral( const int i )
{
  if( i>=0 && i<myData.size()-1 )
    return integral( i, myData[2*(i+1)]-myData[2*i] );
  else
    return 0;
}

double FunctionTable::integral( const int i, const double d )
{
  double f, res = 0.0;
  if( value( myData[2*i]+d, f ) )
    res = ( myData[2*i] + f ) / 2.0 * d;

  return res;
}

double FunctionTable::integral( const double a, const double b )
{
  int x1s, x1f, x2s, x2f;
  findBounds( a, x1s, x1f );
  findBounds( b, x2s, x2f );
  double J = 0;
  for( int i=x1s; i<x2s; i++ )
    J+=integral( i );
  J-=integral( x1s, a-myData[2*x1s] );
  J+=integral( x2s, b-myData[2*x2s] );
  return J;
}

bool FunctionTable::findBounds( const double x, int& x_ind_1, int& x_ind_2 ) const
{
  int n = myData.size();
  if( n==0 || x<myData[0] )
  {
    x_ind_1 = x_ind_2 = 0;
    return false;
  }

  for( int i=0; i<n-1; i++ )
    if( myData[2*i]<=x && x<=myData[2*(i+1)] )
    {
      x_ind_1 = i;
      x_ind_2 = i+1;
      return true;
    }
  x_ind_1 = n-1;
  x_ind_2 = n-1;
  return false;
}



class FunctionExpr : public Function, public math_Function
{
public:
  FunctionExpr( const char*, const bool );
  virtual ~FunctionExpr();
  virtual Standard_Boolean Value( Standard_Real, Standard_Real& );
  virtual bool   value( const double, double& );  //inherited from Function
  virtual double integral( const double, const double );

private:
  Handle(ExprIntrp_GenExp)    myExpr;
  Expr_Array1OfNamedUnknown   myVars;
  TColStd_Array1OfReal        myValues;
};

FunctionExpr::FunctionExpr( const char* str, const bool exp )
: Function( exp ),
  myVars( 1, 1 ),
  myValues( 1, 1 )
{
  myExpr = ExprIntrp_GenExp::Create();
  myExpr->Process( ( Standard_CString )str );
  if( !myExpr->IsDone() )
    myExpr.Nullify();

  myVars.ChangeValue( 1 ) = new Expr_NamedUnknown( "t" );
}

FunctionExpr::~FunctionExpr()
{
}

Standard_Boolean FunctionExpr::Value( Standard_Real T, Standard_Real& F )
{
  double f;
  Standard_Boolean res = value( T, f );
  F = f;
  return res;
}

bool FunctionExpr::value( const double t, double& f )
{
  if( myExpr.IsNull() )
    return false;

  CASCatch_CatchSignals aCatchSignals;
  aCatchSignals.Activate();

  myValues.ChangeValue( 1 ) = t;
  bool ok = true;
  CASCatch_TRY {
    f = myExpr->Expression()->Evaluate( myVars, myValues );
  }
  CASCatch_CATCH(CASCatch_Failure) {
    aCatchSignals.Deactivate();
    Handle(CASCatch_Failure) aFail = CASCatch_Failure::Caught();
    f = 0.0;
  }

  aCatchSignals.Deactivate();
  ok = Function::value( t, f ) && ok;
  return ok;
}

double FunctionExpr::integral( const double a, const double b )
{
  double res = 0.0;
  CASCatch_TRY
  {
    math_GaussSingleIntegration _int( *this, a, b, 20 );
    if( _int.IsDone() )
      res = _int.Value();
  }
  CASCatch_CATCH(CASCatch_Failure)
  {
    res = 0.0;
    MESSAGE( "Exception in integral calculating" );
  }
  return res;
}







double dihotomySolve( Function& f, const double val, const double _start, const double _fin, const double eps, bool& ok )
{
  double start = _start, fin = _fin, start_val, fin_val; bool ok1, ok2;
  ok1 = f.value( start, start_val );
  ok2 = f.value( fin, fin_val );

  if( !ok1 || !ok2 )
  {
    ok = false;
    return 0.0;
  }

  bool start_pos = start_val>=val, fin_pos = fin_val>=val;
  ok = true;
  
  while( fin-start>eps )
  {
    double mid = ( start+fin )/2.0, mid_val;
    ok = f.value( mid, mid_val );
    if( !ok )
      return 0.0;

//    char buf[1024];
//    sprintf( buf, "start=%f\nfin=%f\nmid_val=%f\n", float( start ), float( fin ), float( mid_val ) );
//    MESSAGE( buf );

    bool mid_pos = mid_val>=val;
    if( start_pos!=mid_pos )
    {
      fin_pos = mid_pos;
      fin = mid;
    }
    else if( fin_pos!=mid_pos )
    {
      start_pos = mid_pos;
      start = mid;
    }
    else
      break;
  }
  return (start+fin)/2.0;
}

static bool computeParamByFunc(Adaptor3d_Curve& C3d, double first, double last,
                               double length, bool theReverse, 
                               int nbSeg, Function& func,
                               list<double>& theParams)
{
  OSD::SetSignal( true );
  if( nbSeg<=0 )
    return false;

  MESSAGE( "computeParamByFunc" );

  int nbPnt = 1 + nbSeg;
  vector<double> x(nbPnt, 0.);

  x[0] = 0.0;
  double J = func.integral( 0.0, 1.0 ) / nbSeg;
  bool ok;
  for( int i=1; i<nbSeg; i++ )
  {
    FunctionIntegral f_int( &func, x[i-1] );
    x[i] = dihotomySolve( f_int, J, x[i-1], 1.0, 1E-4, ok );
    if( !ok )
      return false;
  }

  x[nbSeg] = 1.0;
  MESSAGE( "Points:\n" );
  char buf[1024];
  for( int i=0; i<=nbSeg; i++ )
  {
    sprintf(  buf, "%f\n", float(x[i] ) );
    MESSAGE( buf );
  }
    


  // apply parameters in range [0,1] to the space of the curve
  double prevU = first;
  double sign = 1.;
  if (theReverse)
  {
    prevU = last;
    sign = -1.;
  }
  for( int i = 1; i < nbSeg; i++ )
  {
    double curvLength = length * (x[i] - x[i-1]) * sign;
    GCPnts_AbscissaPoint Discret( C3d, curvLength, prevU );
    if ( !Discret.IsDone() )
      return false;
    double U = Discret.Parameter();
    if ( U > first && U < last )
      theParams.push_back( U );
    else
      return false;
    prevU = U;
  }
  return true;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================
bool StdMeshers_Regular_1D::computeInternalParameters(const TopoDS_Edge& theEdge,
                                                      list<double> &     theParams,
                                                      const bool         theReverse) const
{
  theParams.clear();

  double f, l;
  Handle(Geom_Curve) Curve = BRep_Tool::Curve(theEdge, f, l);
  GeomAdaptor_Curve C3d(Curve);

  double length = EdgeLength(theEdge);

  switch( _hypType )
  {
  case LOCAL_LENGTH:
  case NB_SEGMENTS: {

    double eltSize = 1;
    if ( _hypType == LOCAL_LENGTH )
    {
      // Local Length hypothesis
      double nbseg = ceil(length / _value[ BEG_LENGTH_IND ]); // integer sup
      if (nbseg <= 0)
        nbseg = 1;                        // degenerated edge
      eltSize = length / nbseg;
    }
    else
    {
      // Number Of Segments hypothesis
      switch (_ivalue[ DISTR_TYPE_IND ])
      {
      case StdMeshers_NumberOfSegments::DT_Scale:
        {
          double scale = _value[ SCALE_FACTOR_IND ];
          if ( theReverse )
            scale = 1. / scale;
          double alpha = pow( scale , 1.0 / (_ivalue[ NB_SEGMENTS_IND ] - 1));
          double factor = (l - f) / (1 - pow( alpha,_ivalue[ NB_SEGMENTS_IND ]));

          int i, NbPoints = 1 + _ivalue[ NB_SEGMENTS_IND ];
          for ( i = 2; i < NbPoints; i++ )
          {
            double param = f + factor * (1 - pow(alpha, i - 1));
            theParams.push_back( param );
          }
          return true;
        }
        break;
      case StdMeshers_NumberOfSegments::DT_TabFunc:
        {
          FunctionTable func(_vvalue[ TAB_FUNC_IND ], (bool)_ivalue[ EXP_MODE_IND ]);
          return computeParamByFunc(C3d, f, l, length, theReverse,
                                    _ivalue[ NB_SEGMENTS_IND ], func,
                                    theParams);
        }
        break;
      case StdMeshers_NumberOfSegments::DT_ExprFunc:
        {
          FunctionExpr func(_svalue[ EXPR_FUNC_IND ].c_str(), (bool)_ivalue[ EXP_MODE_IND ]);
          return computeParamByFunc(C3d, f, l, length, theReverse,
                                    _ivalue[ NB_SEGMENTS_IND ], func,
                                    theParams);
        }
        break;
      case StdMeshers_NumberOfSegments::DT_Regular:
        eltSize = length / _ivalue[ NB_SEGMENTS_IND ];
        break;
      default:
        return false;
      }
    }

    GCPnts_UniformAbscissa Discret(C3d, eltSize, f, l);
    if ( !Discret.IsDone() )
      return false;

    int NbPoints = Discret.NbPoints();
    for ( int i = 2; i < NbPoints; i++ )
    {
      double param = Discret.Parameter(i);
      theParams.push_back( param );
    }
    return true;
  }

  case BEG_END_LENGTH: {

    // geometric progression: SUM(n) = ( a1 - an * q ) / ( 1 - q ) = length

    double a1 = _value[ BEG_LENGTH_IND ];
    double an = _value[ END_LENGTH_IND ];
    double q  = ( length - a1 ) / ( length - an );

    double U1 = theReverse ? l : f;
    double Un = theReverse ? f : l;
    double param = U1;
    double eltSize = theReverse ? -a1 : a1;
    while ( 1 ) {
      // computes a point on a curve <C3d> at the distance <eltSize>
      // from the point of parameter <param>.
      GCPnts_AbscissaPoint Discret( C3d, eltSize, param );
      if ( !Discret.IsDone() ) break;
      param = Discret.Parameter();
      if ( param > f && param < l )
        theParams.push_back( param );
      else
        break;
      eltSize *= q;
    }
    compensateError( a1, an, U1, Un, length, C3d, theParams );
    return true;
  }

  case ARITHMETIC_1D: {

    // arithmetic progression: SUM(n) = ( an - a1 + q ) * ( a1 + an ) / ( 2 * q ) = length

    double a1 = _value[ BEG_LENGTH_IND ];
    double an = _value[ END_LENGTH_IND ];

    double  q = ( an - a1 ) / ( 2 *length/( a1 + an ) - 1 );
    int     n = int( 1 + ( an - a1 ) / q );

    double U1 = theReverse ? l : f;
    double Un = theReverse ? f : l;
    double param = U1;
    double eltSize = a1;
    if ( theReverse ) {
      eltSize = -eltSize;
      q = -q;
    }
    while ( n-- > 0 && eltSize * ( Un - U1 ) > 0 ) {
      // computes a point on a curve <C3d> at the distance <eltSize>
      // from the point of parameter <param>.
      GCPnts_AbscissaPoint Discret( C3d, eltSize, param );
      if ( !Discret.IsDone() ) break;
      param = Discret.Parameter();
      if ( param > f && param < l )
        theParams.push_back( param );
      else
        break;
      eltSize += q;
    }
    compensateError( a1, an, U1, Un, length, C3d, theParams );

    return true;
  }

  case DEFLECTION: {

    GCPnts_UniformDeflection Discret(C3d, _value[ DEFLECTION_IND ], true);
    if ( !Discret.IsDone() )
      return false;

    int NbPoints = Discret.NbPoints();
    for ( int i = 2; i < NbPoints; i++ )
    {
      double param = Discret.Parameter(i);
      theParams.push_back( param );
    }
    return true;
    
  }

  default:;
  }

  return false;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

bool StdMeshers_Regular_1D::Compute(SMESH_Mesh & aMesh, const TopoDS_Shape & aShape)
{
  MESSAGE("StdMeshers_Regular_1D::Compute");

  if ( _hypType == NONE )
    return false;

  SMESHDS_Mesh * meshDS = aMesh.GetMeshDS();
  aMesh.GetSubMesh(aShape);

  const TopoDS_Edge & EE = TopoDS::Edge(aShape);
  TopoDS_Edge E = TopoDS::Edge(EE.Oriented(TopAbs_FORWARD));
  int shapeID = meshDS->ShapeToIndex( E );

  double f, l;
  Handle(Geom_Curve) Curve = BRep_Tool::Curve(E, f, l);

  TopoDS_Vertex VFirst, VLast;
  TopExp::Vertices(E, VFirst, VLast);   // Vfirst corresponds to f and Vlast to l

  ASSERT(!VFirst.IsNull());
  SMDS_NodeIteratorPtr lid= aMesh.GetSubMesh(VFirst)->GetSubMeshDS()->GetNodes();
  if (!lid->more())
  {
    MESSAGE (" NO NODE BUILT ON VERTEX ");
    return false;
  }
  const SMDS_MeshNode * idFirst = lid->next();

  ASSERT(!VLast.IsNull());
  lid=aMesh.GetSubMesh(VLast)->GetSubMeshDS()->GetNodes();
  if (!lid->more())
  {
    MESSAGE (" NO NODE BUILT ON VERTEX ");
    return false;
  }
  const SMDS_MeshNode * idLast = lid->next();

  if (!Curve.IsNull())
  {
    list< double > params;
    bool reversed = false;
    if ( !_mainEdge.IsNull() )
      reversed = aMesh.IsReversedInChain( EE, _mainEdge );
    try {
      if ( ! computeInternalParameters( E, params, reversed ))
        return false;
    }
    catch ( Standard_Failure ) {
      return false;
    }

    // edge extrema (indexes : 1 & NbPoints) already in SMDS (TopoDS_Vertex)
    // only internal nodes receive an edge position with param on curve

    const SMDS_MeshNode * idPrev = idFirst;
    
    for (list<double>::iterator itU = params.begin(); itU != params.end(); itU++)
    {
      double param = *itU;
      gp_Pnt P = Curve->Value(param);

      //Add the Node in the DataStructure
      SMDS_MeshNode * node = meshDS->AddNode(P.X(), P.Y(), P.Z());
      meshDS->SetNodeOnEdge(node, shapeID, param);

      SMDS_MeshEdge * edge = meshDS->AddEdge(idPrev, node);
      meshDS->SetMeshElementOnShape(edge, shapeID);
      idPrev = node;
    }
    SMDS_MeshEdge* edge = meshDS->AddEdge(idPrev, idLast);
    meshDS->SetMeshElementOnShape(edge, shapeID);
  }
  else
  {
    // Edge is a degenerated Edge : We put n = 5 points on the edge.
    int NbPoints = 5;
    BRep_Tool::Range(E, f, l);
    double du = (l - f) / (NbPoints - 1);
    //MESSAGE("************* Degenerated edge! *****************");

    TopoDS_Vertex V1, V2;
    TopExp::Vertices(E, V1, V2);
    gp_Pnt P = BRep_Tool::Pnt(V1);

    const SMDS_MeshNode * idPrev = idFirst;
    for (int i = 2; i < NbPoints; i++)
    {
      double param = f + (i - 1) * du;
      SMDS_MeshNode * node = meshDS->AddNode(P.X(), P.Y(), P.Z());
      meshDS->SetNodeOnEdge(node, shapeID, param);

      SMDS_MeshEdge * edge = meshDS->AddEdge(idPrev, node);
      meshDS->SetMeshElementOnShape(edge, shapeID);
      idPrev = node;
    }
    SMDS_MeshEdge * edge = meshDS->AddEdge(idPrev, idLast);
    meshDS->SetMeshElementOnShape(edge, shapeID);
  }
  return true;
}

//=============================================================================
/*!
 *  See comments in SMESH_Algo.cxx
 */
//=============================================================================

const list <const SMESHDS_Hypothesis *> & StdMeshers_Regular_1D::GetUsedHypothesis(
	SMESH_Mesh & aMesh, const TopoDS_Shape & aShape)
{
  _usedHypList.clear();
  _usedHypList = GetAppliedHypothesis(aMesh, aShape);	// copy
  int nbHyp = _usedHypList.size();
  _mainEdge.Nullify();
  if (nbHyp == 0)
  {
    // Check, if propagated from some other edge
    if (aShape.ShapeType() == TopAbs_EDGE &&
        aMesh.IsPropagatedHypothesis(aShape, _mainEdge))
    {
      // Propagation of 1D hypothesis from <aMainEdge> on this edge
      //_usedHypList = GetAppliedHypothesis(aMesh, _mainEdge);	// copy
      // use a general method in order not to nullify _mainEdge
      _usedHypList = SMESH_Algo::GetUsedHypothesis(aMesh, _mainEdge);	// copy
      nbHyp = _usedHypList.size();
    }
  }
  if (nbHyp == 0)
  {
    TopTools_ListIteratorOfListOfShape ancIt( aMesh.GetAncestors( aShape ));
    for (; ancIt.More(); ancIt.Next())
    {
      const TopoDS_Shape& ancestor = ancIt.Value();
      _usedHypList = GetAppliedHypothesis(aMesh, ancestor);	// copy
      nbHyp = _usedHypList.size();
      if (nbHyp == 1)
        break;
    }
  }
  if (nbHyp > 1)
    _usedHypList.clear();	//only one compatible hypothesis allowed
  return _usedHypList;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

ostream & StdMeshers_Regular_1D::SaveTo(ostream & save)
{
  return save;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

istream & StdMeshers_Regular_1D::LoadFrom(istream & load)
{
  return load;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

ostream & operator <<(ostream & save, StdMeshers_Regular_1D & hyp)
{
  return hyp.SaveTo( save );
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

istream & operator >>(istream & load, StdMeshers_Regular_1D & hyp)
{
  return hyp.LoadFrom( load );
}