// Copyright (c) 1997-1999 Matra Datavision
// Copyright (c) 1999-2012 OPEN CASCADE SAS
//
// The content of this file is subject to the Open CASCADE Technology Public
// License Version 6.5 (the "License"). You may not use the content of this file
// except in compliance with the License. Please obtain a copy of the License
// at http://www.opencascade.org and read it completely before using this file.
//
// The Initial Developer of the Original Code is Open CASCADE S.A.S., having its
// main offices at: 1, place des Freres Montgolfier, 78280 Guyancourt, France.
//
// The Original Code and all software distributed under the License is
// distributed on an "AS IS" basis, without warranty of any kind, and the
// Initial Developer hereby disclaims all such warranties, including without
// limitation, any warranties of merchantability, fitness for a particular
// purpose or non-infringement. Please see the License for the specific terms
// and conditions governing the rights and limitations under the License.

//#ifndef DEB
#define No_Standard_RangeError
#define No_Standard_OutOfRange
#define No_Standard_DimensionError
//#endif

#include <math_Gauss.ixx>
#include <math_Recipes.hxx>

#include <math_NotSquare.hxx> 
#include <StdFail_NotDone.hxx>
#include <Standard_DimensionError.hxx>
#include <Standard_NotImplemented.hxx>

math_Gauss::math_Gauss(const math_Matrix& A, 
                           const Standard_Real MinPivot) 
                           : LU   (1, A.RowNumber(), 1, A.ColNumber()),
                             Index(1, A.RowNumber()) {

      math_NotSquare_Raise_if(A.RowNumber() != A.ColNumber(), " ");     
      LU = A;
      Standard_Integer Error = LU_Decompose(LU, 
                                  Index, 
                                  D,
                                  MinPivot);
      if(!Error) {
        Done = Standard_True;
      }
      else {
        Done = Standard_False;
      }
    }

    void  math_Gauss::Solve(const math_Vector& B, math_Vector& X) const{

       StdFail_NotDone_Raise_if(!Done, " ");

       X = B;
       LU_Solve(LU,
                Index,
                X);
    }

    void math_Gauss::Solve (math_Vector& X) const{

       StdFail_NotDone_Raise_if(!Done, " ");

       if(X.Length() != LU.RowNumber()) {
         Standard_DimensionError::Raise();
       }
       LU_Solve(LU,
                Index,
                X);
    }

    Standard_Real math_Gauss::Determinant() const{

       StdFail_NotDone_Raise_if(!Done, " ");

       Standard_Real Result = D;
       for(Standard_Integer J = 1; J <= LU.UpperRow(); J++) {
         Result *= LU(J,J);
       }
       return Result;
    }

    void math_Gauss::Invert(math_Matrix& Inv) const{

       StdFail_NotDone_Raise_if(!Done, " ");

       Standard_DimensionError_Raise_if((Inv.RowNumber() != LU.RowNumber()) ||
					(Inv.ColNumber() != LU.ColNumber()),
					" ");

       Standard_Integer LowerRow = Inv.LowerRow();
       Standard_Integer LowerCol = Inv.LowerCol();
       math_Vector Column(1, LU.UpperRow());

       Standard_Integer I, J;
       for(J = 1; J <= LU.UpperRow(); J++) {
         for(I = 1; I <= LU.UpperRow(); I++) {
           Column(I) = 0.0;
         }
         Column(J) = 1.0;
         LU_Solve(LU, Index, Column);
         for(I = 1; I <= LU.RowNumber(); I++) {
           Inv(I+LowerRow-1,J+LowerCol-1) = Column(I);
         }
       }

    }


void math_Gauss::Dump(Standard_OStream& o) const {
       o << "math_Gauss ";
       if(Done) {
         o<< " Status = Done \n";
	 o << " Determinant of A = " << D << endl;
       }
       else {
         o << " Status = not Done \n";
       }
    }