ReplicatableVector.cpp

/*

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*/

#include "ReplicatableVector.hpp"
#include "Exception.hpp"
#include "PetscTools.hpp"

#include <cassert>
#include <iostream>

// Private methods

void ReplicatableVector::RemovePetscContext()
{
    if (mToAll != NULL)
    {
        VecScatterDestroy(PETSC_DESTROY_PARAM(mToAll));
        mToAll = NULL;
    }

    if (mReplicated != NULL)
    {
        PetscTools::Destroy(mReplicated);
        mReplicated = NULL;
    }

    if (mpData != NULL)
    {
        delete[] mpData;
        mpData = NULL;
    }
}

// Constructors & destructors

ReplicatableVector::ReplicatableVector()
    : mpData(NULL),
      mSize(0),
      mToAll(NULL),
      mReplicated(NULL)
{
}

ReplicatableVector::ReplicatableVector(Vec vec)
    : mpData(NULL),
      mSize(0),
      mToAll(NULL),
      mReplicated(NULL)
{
    ReplicatePetscVector(vec);
}

ReplicatableVector::ReplicatableVector(unsigned size)
    : mpData(NULL),
      mSize(0),
      mToAll(NULL),
      mReplicated(NULL)
{
    Resize(size);
}

ReplicatableVector::~ReplicatableVector()
{
    RemovePetscContext();
}

// Vector interface methods

unsigned ReplicatableVector::GetSize()
{
    return mSize;
}

void ReplicatableVector::Resize(unsigned size)
{
    // PETSc stuff will be out of date
    RemovePetscContext();

    mSize = size;

    try
    {
        mpData = new double[mSize];
    }
    catch(std::bad_alloc &badAlloc)
    {
#define COVERAGE_IGNORE
        std::cout << "Failed to allocate a ReplicatableVector of size " << size  << std::endl;
        PetscTools::ReplicateException(true);
        throw badAlloc;
#undef COVERAGE_IGNORE
    }
    PetscTools::ReplicateException(false);
}

double& ReplicatableVector::operator[](unsigned index)
{
    assert(index < mSize);
    return mpData[index];
}

// The workhorse methods

void ReplicatableVector::Replicate(unsigned lo, unsigned hi)
{
    // Create a PetSC vector with the array containing the distributed data
    Vec distributed_vec;
    VecCreateMPIWithArray(PETSC_COMM_WORLD, hi-lo, this->GetSize(), &mpData[lo], &distributed_vec);

    // Now do the real replication
    ReplicatePetscVector(distributed_vec);

    // Clean up
    PetscTools::Destroy(distributed_vec);
}

void ReplicatableVector::ReplicatePetscVector(Vec vec)
{
    // If the size has changed then we'll need to make a new context
    PetscInt isize;
    VecGetSize(vec, &isize);
    unsigned size = isize;

    if (this->GetSize() != size)
    {
        Resize(size);
    }
    if (mReplicated == NULL)
    {
        // This creates mToAll (the scatter context) and mReplicated (to store values)
        VecScatterCreateToAll(vec, &mToAll, &mReplicated);
    }

    // Replicate the data
//PETSc-3.x.x or PETSc-2.3.3
#if ( (PETSC_VERSION_MAJOR == 3) || (PETSC_VERSION_MAJOR == 2 && PETSC_VERSION_MINOR == 3 && PETSC_VERSION_SUBMINOR == 3)) //2.3.3 or 3.x.x
    VecScatterBegin(mToAll, vec, mReplicated, INSERT_VALUES, SCATTER_FORWARD);
    VecScatterEnd  (mToAll, vec, mReplicated, INSERT_VALUES, SCATTER_FORWARD);
#else
//PETSc-2.3.2 or previous
    VecScatterBegin(vec, mReplicated, INSERT_VALUES, SCATTER_FORWARD, mToAll);
    VecScatterEnd  (vec, mReplicated, INSERT_VALUES, SCATTER_FORWARD, mToAll);
#endif

    // Information is now in mReplicated PETSc vector
    // Copy into mData
    double* p_replicated;
    VecGetArray(mReplicated, &p_replicated);
    for (unsigned i=0; i<size; i++)
    {
        mpData[i] = p_replicated[i];
    }
}