PetscVecTools.hpp

/*

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*/

#ifndef _PETSCVECTOOLS_HPP_
#define _PETSCVECTOOLS_HPP_

#include "UblasVectorInclude.hpp" // needs to be 'first'

#include <petscvec.h>

class PetscVecTools
{
public:

    static void Finalise(Vec vector);

    static void Display(Vec vector);

    static void Zero(Vec vector);

    static void SetElement(Vec vector, PetscInt row, double value);

    static void AddToElement(Vec vector, PetscInt row, double value);

    static unsigned GetSize(Vec vector);

    static void GetOwnershipRange(Vec vector, PetscInt& lo, PetscInt& hi);

    static double GetElement(Vec vector, PetscInt row);

    static void AddScaledVector(Vec y, Vec x, double scaleFactor);

    static void Scale(Vec vector, double scaleFactor);

    static void WAXPY(Vec w, double a, Vec x, Vec y);

    template<size_t VECTOR_SIZE>
    static void AddMultipleValues(Vec vector, unsigned* vectorIndices, c_vector<double, VECTOR_SIZE>& smallVector)
    {
        PetscInt indices_owned[VECTOR_SIZE];
        PetscInt num_indices_owned = 0;
        PetscInt global_row;
        PetscInt lo, hi;
        GetOwnershipRange(vector, lo, hi);

        for (unsigned row = 0; row<VECTOR_SIZE; row++)
        {
            global_row = vectorIndices[row];
            if (global_row >=lo && global_row <hi)
            {
                indices_owned[num_indices_owned++] = global_row;
            }
        }

        if (num_indices_owned == VECTOR_SIZE)
        {
            VecSetValues(vector,
                         num_indices_owned,
                         indices_owned,
                         smallVector.data(),
                         ADD_VALUES);
        }
        else
        {
            /*
             * We need continuous data, if some of the rows do not belong
             * to the processor their values are not passed to VecSetValues.
             */
            double values[VECTOR_SIZE];
            unsigned num_values_owned = 0;

            for (unsigned row = 0; row<VECTOR_SIZE; row++)
            {
                global_row = vectorIndices[row];
                if (global_row >= lo && global_row < hi)
                {
                    values[num_values_owned++] = smallVector(row);
                }
            }

            VecSetValues(vector,
                         num_indices_owned,
                         indices_owned,
                         values,
                         ADD_VALUES);
        }
    }

    static void SetupInterleavedVectorScatterGather(Vec interleavedVec, VecScatter& rFirstVariableScatterContext, VecScatter& rSecondVariableScatterContext);

    static void DoInterleavedVecScatter(Vec interleavedVec, VecScatter firstVariableScatterContext, Vec firstVariableVec, VecScatter secondVariableScatterContext, Vec secondVariableVec);

    static void DoInterleavedVecGather(Vec interleavedVec, VecScatter firstVariableScatterContext, Vec firstVariableVec, VecScatter secondVariableScatterContext, Vec secondVariableVec);
};

#endif //_PETSCVECTOOLS_HPP_