OdeLinearSystemSolver.cpp

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#include "OdeLinearSystemSolver.hpp"
#include "PetscTools.hpp"
#include "ReplicatableVector.hpp"

OdeLinearSystemSolver::OdeLinearSystemSolver(unsigned systemSize, double timeStep)
    : mLinearSystem(systemSize)
{
    assert(timeStep > 0.0);
    mTimeStep = timeStep;

    // Initialise vectors to zero
    mCurrentSolution = PetscTools::CreateAndSetVec(systemSize, 0.0);
    mForceVector = PetscTools::CreateAndSetVec(systemSize, 0.0);
}

OdeLinearSystemSolver::~OdeLinearSystemSolver()
{
    PetscTools::Destroy(mCurrentSolution);
    PetscTools::Destroy(mForceVector);
}

double OdeLinearSystemSolver::GetTimeStep()
{
    return mTimeStep;
}

Mat& OdeLinearSystemSolver::rGetLhsMatrix()
{
    return mLinearSystem.rGetLhsMatrix();
}

Vec& OdeLinearSystemSolver::rGetForceVector()
{
    return mForceVector;
}

void OdeLinearSystemSolver::SetInitialConditionVector(Vec initialConditionsVector)
{
    VecCopy(initialConditionsVector, mCurrentSolution);
}

Vec OdeLinearSystemSolver::SolveOneTimeStep()
{
    // Compute the product of the LHS matrix and the current solution vector,
    // setting the answer to be the RHS vector
    MatMult(mLinearSystem.rGetLhsMatrix(), mCurrentSolution, mLinearSystem.rGetRhsVector());

    // Add timestep multipled by force vector
    PetscVecTools::AddScaledVector(mLinearSystem.rGetRhsVector(), mForceVector, mTimeStep);

    // avoid memory leaks
    PetscTools::Destroy(mCurrentSolution);

    // Having constructed the RHS vector, solve the resulting linear system...
    mCurrentSolution = mLinearSystem.Solve();

    return mCurrentSolution;
}