//
// Software License for AMDiS
//
// Copyright (c) 2010 Dresden University of Technology 
// All rights reserved.
// Authors: Simon Vey, Thomas Witkowski et al.
//
// This file is part of AMDiS
//
// See also license.opensource.txt in the distribution.


#include "parallel/PetscHelper.h"

namespace AMDiS {

  namespace petsc_helper {

    using namespace std;
    
    void getMatLocalColumn(Mat mat, PetscMatCol &matCol)
    {
      PetscInt firstIndex, lastIndex;
      MatGetOwnershipRange(mat, &firstIndex, &lastIndex);
    
      PetscInt nCols;
      const PetscInt *cols;
      const PetscScalar *values;
      
      for (int row = firstIndex; row < lastIndex; row++) {
	MatGetRow(mat, row, &nCols, &cols, &values);
	
	for (int i = 0; i < nCols; i++) {
	  if (values[i] != 0.0) {
	    matCol[cols[i]].first.push_back(row - firstIndex);
	    matCol[cols[i]].second.push_back(values[i]);
	  }
	}

	MatRestoreRow(mat, row, &nCols, &cols, &values);
      }
    }


    void setMatLocalColumn(Mat mat, int column, Vec vec)
    {
      PetscInt firstIndex;
      MatGetOwnershipRange(mat, &firstIndex, PETSC_NULL);

      PetscInt vecSize;
      VecGetLocalSize(vec, &vecSize);

      PetscScalar *tmpValues;
      VecGetArray(vec, &tmpValues);
      for (int i  = 0; i < vecSize; i++)
	MatSetValue(mat, 
		    firstIndex + i,
		    column,
		    tmpValues[i],
		    ADD_VALUES);
      VecRestoreArray(vec, &tmpValues);
    }


    void getColumnVec(const SparseCol &matCol, Vec vec)
    {
      VecSet(vec, 0.0);
      VecSetValues(vec, matCol.first.size(), 
		   &(matCol.first[0]), &(matCol.second[0]), INSERT_VALUES);
      VecAssemblyBegin(vec);
      VecAssemblyEnd(vec);
    }
  }
  
}