PetscTools.cpp

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#include "PetscTools.hpp"
#include "Exception.hpp"
#include "Warnings.hpp"
#include <iostream>
#include <sstream>
#include <cassert>
#include <cstring> // For strcmp etc. Needed in gcc-4.3

bool PetscTools::mPetscIsInitialised = false;
unsigned PetscTools::mNumProcessors = 0;
unsigned PetscTools::mRank = 0;
bool PetscTools::mIsolateProcesses = false;

#ifndef NDEBUG
// Uncomment this to trace calls to PetscTools::Barrier
//#define DEBUG_BARRIERS
#endif

#ifdef DEBUG_BARRIERS
static unsigned mNumBarriers = 0u;
#endif

void PetscTools::ResetCache()
{
    PetscBool is_there;
    PetscInitialized(&is_there);
    if (is_there)
    {
        mPetscIsInitialised = true;

        PetscInt num_procs;
        MPI_Comm_size(PETSC_COMM_WORLD, &num_procs);
        mNumProcessors = (unsigned) num_procs;

        PetscInt my_rank;
        MPI_Comm_rank(PETSC_COMM_WORLD, &my_rank);
        mRank = (unsigned) my_rank;
    }
    else
    {
        // No PETSc
        mPetscIsInitialised = false;
        mNumProcessors = 1;
        mRank = 0;
    }
}

// Information methods

bool PetscTools::IsInitialised()
{
    CheckCache();
    return mPetscIsInitialised;
}

bool PetscTools::IsSequential()
{
    CheckCache();
    return (mIsolateProcesses || mNumProcessors == 1);
}

bool PetscTools::IsParallel()
{
    CheckCache();
    return (mNumProcessors > 1);
}

bool PetscTools::IsIsolated()
{
    return mIsolateProcesses;
}

unsigned PetscTools::GetNumProcs()
{
    CheckCache();
    return mNumProcessors;
}

unsigned PetscTools::GetMyRank()
{
    CheckCache();
    return mRank;
}

bool PetscTools::AmMaster()
{
    CheckCache();
    return (mRank == MASTER_RANK || mIsolateProcesses);
}

bool PetscTools::AmTopMost()
{
    CheckCache();
    return (mRank == mNumProcessors - 1 || mIsolateProcesses);
}

// Little utility methods

void PetscTools::Barrier(const std::string callerId)
{
    CheckCache();
    if (mPetscIsInitialised && !mIsolateProcesses)
    {
#ifdef DEBUG_BARRIERS
        std::cout << "DEBUG: proc " << PetscTools::GetMyRank() << ": Pre " << callerId << " Barrier " << mNumBarriers << "." << std::endl << std::flush;
#endif
        PetscBarrier(PETSC_NULL);
#ifdef DEBUG_BARRIERS
        std::cout << "DEBUG: proc " << PetscTools::GetMyRank() << ": Post " << callerId << " Barrier " << mNumBarriers++ << "." << std::endl << std::flush;
#endif
    }
}

void PetscTools::BeginRoundRobin()
{
    Barrier("PetscTools::RoundRobin"); // We want barriers both before all and after all, just in case
    const unsigned my_rank = GetMyRank();
    for (unsigned turn=0; turn<my_rank; turn++)
    {
        Barrier("PetscTools::RoundRobin");
    }
}

void PetscTools::EndRoundRobin()
{
    const unsigned num_procs = GetNumProcs();
    for (unsigned turn=GetMyRank(); turn<num_procs; turn++)
    {
        Barrier("PetscTools::RoundRobin");
    }
}

void PetscTools::IsolateProcesses(bool isolate)
{
    mIsolateProcesses = isolate;
}

MPI_Comm PetscTools::GetWorld()
{
    if (mIsolateProcesses)
    {
        return PETSC_COMM_SELF;
    }
    else
    {
        return PETSC_COMM_WORLD;
    }
}

bool PetscTools::ReplicateBool(bool flag)
{
    CheckCache();
    unsigned my_flag = (unsigned) flag;
    unsigned anyones_flag_is_true = my_flag;
    if (mPetscIsInitialised && !mIsolateProcesses)
    {
        MPI_Allreduce(&my_flag, &anyones_flag_is_true, 1, MPI_UNSIGNED, MPI_MAX, PETSC_COMM_WORLD);
    }
    return (anyones_flag_is_true == 1);
}

void PetscTools::ReplicateException(bool flag)
{
    bool anyones_error=ReplicateBool(flag);
    if (flag)
    {
        // Return control to exception thrower
        return;
    }
    if (anyones_error)
    {
        EXCEPTION("Another process threw an exception; bailing out.");
    }
}

// Vector & matrix creation routines

Vec PetscTools::CreateVec(int size, int localSize, bool ignoreOffProcEntries)
{
    assert(size >= 0); // There is one test where we create a zero-sized vector
    Vec ret;
    VecCreate(PETSC_COMM_WORLD, &ret);
    VecSetSizes(ret, localSize, size); // localSize usually defaults to PETSC_DECIDE
    VecSetFromOptions(ret);

    if (ignoreOffProcEntries)
    {
#if (PETSC_VERSION_MAJOR == 3) //PETSc 3.x.x
        VecSetOption(ret, VEC_IGNORE_OFF_PROC_ENTRIES, PETSC_TRUE);
#else
        VecSetOption(ret, VEC_IGNORE_OFF_PROC_ENTRIES);
#endif
    }

    return ret;
}

Vec PetscTools::CreateVec(std::vector<double> data)
{
    assert(data.size() > 0);
    Vec ret = CreateVec(data.size());

    double* p_ret;
    VecGetArray(ret, &p_ret);
    int lo, hi;
    VecGetOwnershipRange(ret, &lo, &hi);

    for (int global_index=lo; global_index<hi; global_index++)
    {
        int local_index = global_index - lo;
        p_ret[local_index] = data[global_index];
    }
    VecRestoreArray(ret, &p_ret);

    return ret;
}

Vec PetscTools::CreateAndSetVec(int size, double value)
{
    assert(size > 0);
    Vec ret = CreateVec(size);

#if (PETSC_VERSION_MAJOR == 2 && PETSC_VERSION_MINOR == 2) //PETSc 2.2
    VecSet(&value, ret);
#else
    VecSet(ret, value);
#endif

    return ret;
}

void PetscTools::SetupMat(Mat& rMat, int numRows, int numColumns,
                          unsigned rowPreallocation,
                          int numLocalRows,
                          int numLocalColumns,
                          bool ignoreOffProcEntries,
                          bool newAllocationError)
{
    assert(numRows > 0);
    assert(numColumns > 0);
    if ((int) rowPreallocation>numColumns)
    {
        WARNING("Preallocation failure: requested number of nonzeros per row greater than number of columns");//+rowPreallocation+">"+numColumns);
        rowPreallocation = numColumns;
    }

#if (PETSC_VERSION_MAJOR == 2 && PETSC_VERSION_MINOR == 2) //PETSc 2.2
    MatCreate(PETSC_COMM_WORLD,numLocalRows,numLocalColumns,numRows,numColumns,&rMat);
#else //New API
    MatCreate(PETSC_COMM_WORLD,&rMat);
    MatSetSizes(rMat,numLocalRows,numLocalColumns,numRows,numColumns);
#endif

    if (PetscTools::IsSequential())
    {
        MatSetType(rMat, MATSEQAIJ);
        if (rowPreallocation > 0)
        {
            MatSeqAIJSetPreallocation(rMat, rowPreallocation, PETSC_NULL);
        }
    }
    else
    {
        MatSetType(rMat, MATMPIAIJ);
        if (rowPreallocation > 0)
        {
            MatMPIAIJSetPreallocation(rMat, rowPreallocation, PETSC_NULL, rowPreallocation, PETSC_NULL);
        }
    }

    MatSetFromOptions(rMat);

    if (ignoreOffProcEntries)//&& IsParallel())
    {
        if (rowPreallocation == 0)
        {
            // We aren't allowed to do non-zero allocation after setting MAT_IGNORE_OFF_PROC_ENTRIES
            WARNING("Ignoring MAT_IGNORE_OFF_PROC_ENTRIES flag because we might set non-zeroes later");
        }
        else
        {
#if (PETSC_VERSION_MAJOR == 3) //PETSc 3.x.x
            MatSetOption(rMat, MAT_IGNORE_OFF_PROC_ENTRIES, PETSC_TRUE);
#else
            MatSetOption(rMat, MAT_IGNORE_OFF_PROC_ENTRIES);
#endif
        }
    }
#if (PETSC_VERSION_MAJOR == 3 && PETSC_VERSION_MINOR >= 3) //PETSc 3.3 or later
    if (newAllocationError == false)
    {
        MatSetOption(rMat, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE);
    }
#endif
}

void PetscTools::DumpPetscObject(const Mat& rMat, const std::string& rOutputFileFullPath)
{
    PetscViewer view;
#if (PETSC_VERSION_MAJOR == 2 && PETSC_VERSION_MINOR == 2) //PETSc 2.2
    PetscViewerFileType type = PETSC_FILE_CREATE;
#else
    PetscFileMode type = FILE_MODE_WRITE;
#endif

    PetscViewerBinaryOpen(PETSC_COMM_WORLD, rOutputFileFullPath.c_str(), type, &view);
    MatView(rMat, view);
    PetscViewerDestroy(PETSC_DESTROY_PARAM(view));
}

void PetscTools::DumpPetscObject(const Vec& rVec, const std::string& rOutputFileFullPath)
{
    PetscViewer view;
#if (PETSC_VERSION_MAJOR == 2 && PETSC_VERSION_MINOR == 2) //PETSc 2.2
    PetscViewerFileType type = PETSC_FILE_CREATE;
#else
    PetscFileMode type = FILE_MODE_WRITE;
#endif

    PetscViewerBinaryOpen(PETSC_COMM_WORLD, rOutputFileFullPath.c_str(), type, &view);
    VecView(rVec, view);
    PetscViewerDestroy(PETSC_DESTROY_PARAM(view));
}

void PetscTools::ReadPetscObject(Mat& rMat, const std::string& rOutputFileFullPath, Vec rParallelLayout)
{
    /*
     * PETSc (as of 3.1) doesn't provide any method for loading a Mat object with a user-defined parallel
     * layout, i.e. there's no equivalent to VecLoadIntoVector for Mat's.
     *
     * It seems to be in their future plans though: http://lists.mcs.anl.gov/pipermail/petsc-users/2010-March/006062.html
     */

    PetscViewer view;
#if (PETSC_VERSION_MAJOR == 2 && PETSC_VERSION_MINOR == 2) //PETSc 2.2
    PetscViewerFileType type = PETSC_FILE_RDONLY;
#else
    PetscFileMode type = FILE_MODE_READ;
#endif

    PetscViewerBinaryOpen(PETSC_COMM_WORLD, rOutputFileFullPath.c_str(),
                          type, &view);

#if (PETSC_VERSION_MAJOR == 3 && PETSC_VERSION_MINOR >= 2) //PETSc 3.2 or later
    MatCreate(PETSC_COMM_WORLD,&rMat);
    MatSetType(rMat,MATMPIAIJ);
    MatLoad(rMat,view);
#else
    MatLoad(view, MATMPIAIJ, &rMat);
#endif

    PetscViewerDestroy(PETSC_DESTROY_PARAM(view));

    if (rParallelLayout != NULL)
    {
        /*
         * The idea is to copy rMat into a matrix that has the appropriate
         * parallel layout. Inefficient...
         */
        PetscInt num_rows, num_local_rows;

        VecGetSize(rParallelLayout, &num_rows);
        VecGetLocalSize(rParallelLayout, &num_local_rows);

        Mat temp_mat;
        PetscTools::SetupMat(temp_mat, num_rows, num_rows, 100, num_local_rows, num_local_rows, false);

        MatCopy(rMat, temp_mat, DIFFERENT_NONZERO_PATTERN);

        PetscTools::Destroy(rMat);
        rMat = temp_mat;
    }
}

void PetscTools::ReadPetscObject(Vec& rVec, const std::string& rOutputFileFullPath, Vec rParallelLayout)
{
    PetscViewer view;
#if (PETSC_VERSION_MAJOR == 2 && PETSC_VERSION_MINOR == 2) //PETSc 2.2
    PetscViewerFileType type = PETSC_FILE_RDONLY;
#else
    PetscFileMode type = FILE_MODE_READ;
#endif

    PetscViewerBinaryOpen(PETSC_COMM_WORLD, rOutputFileFullPath.c_str(),
                          type, &view);
    if (rParallelLayout == NULL)
    {
#if (PETSC_VERSION_MAJOR == 3 && PETSC_VERSION_MINOR >= 2) //PETSc 3.2 or later
        VecCreate(PETSC_COMM_WORLD,&rVec);
        VecSetType(rVec,VECMPI);
        VecLoad(rVec,view);
#else
        VecLoad(view, VECMPI, &rVec);
#endif
    }
    else
    {
        VecDuplicate(rParallelLayout, &rVec);
#if (PETSC_VERSION_MAJOR == 3 && PETSC_VERSION_MINOR >= 2) //PETSc 3.2 or later
        VecLoad(rVec,view);
#else
        VecLoadIntoVector(view, rVec);
#endif
    }
    PetscViewerDestroy(PETSC_DESTROY_PARAM(view));
}

bool PetscTools::HasParMetis()
{
#ifdef __INTEL_COMPILER
    //Old versions of the intel compiler can result in a PETSC ERROR and the program aborting if parmetis is checked for before
    //some other calls to Petsc are made. This nasty hack ensures that the HasParMetis method always works on Intel
    Mat mat;
    PetscTools::SetupMat(mat, 1, 1, 1);
    PetscTools::Destroy(mat);
#endif

    MatPartitioning part;
    MatPartitioningCreate(PETSC_COMM_WORLD, &part);


    // We are expecting an error from PETSC on systems that don't have the interface, so suppress it
    // in case it aborts
    PetscPushErrorHandler(PetscIgnoreErrorHandler, NULL);

#if (PETSC_VERSION_MAJOR == 2 || (PETSC_VERSION_MAJOR == 3 && PETSC_VERSION_MINOR < 2))
    PetscErrorCode parmetis_installed_error = MatPartitioningSetType(part,MAT_PARTITIONING_PARMETIS);
#else
    PetscErrorCode parmetis_installed_error = MatPartitioningSetType(part,MATPARTITIONINGPARMETIS);
#endif

    // Stop supressing error
    PetscPopErrorHandler();

    // Note that this method probably leaks memory inside PETSc because if MatPartitioningCreate fails
    // then there isn't a proper handle to destroy.
    MatPartitioningDestroy(PETSC_DESTROY_PARAM(part));
    return (parmetis_installed_error == 0);
}