ApplyWeights.cpp File Reference

#include "moab/Remapping/TempestOnlineMap.hpp"
#include <algorithm>
#include <utility>
#include <vector>

Include dependency graph for ApplyWeights.cpp:

Go to the source code of this file.

Classes
struct	KahanSum

Functions
double	pairwiseSum (const std::set< double > &sorted)
double	pairwiseKahanSum (const std::set< double > &sorted)
void	deterministicSparseMatVecMul (const typename moab::TempestOnlineMap::WeightMatrix &A, const typename moab::TempestOnlineMap::WeightColVector &x, typename moab::TempestOnlineMap::WeightRowVector &result)
void	deterministicSparseMatVecMulKahan (const typename moab::TempestOnlineMap::WeightMatrix &A, const typename moab::TempestOnlineMap::WeightColVector &x, typename moab::TempestOnlineMap::WeightRowVector &result)
void	deterministicSparseMatVecMulClean (const typename moab::TempestOnlineMap::WeightMatrix &A, const typename moab::TempestOnlineMap::WeightColVector &x, typename moab::TempestOnlineMap::WeightRowVector &result)
void	deterministicSparseMatVecMulNative (const typename moab::TempestOnlineMap::WeightMatrix &A, const typename moab::TempestOnlineMap::WeightColVector &x, typename moab::TempestOnlineMap::WeightRowVector &result)
void	deterministicSparseMatTransposeVecMul (const typename moab::TempestOnlineMap::WeightMatrix &A, const typename moab::TempestOnlineMap::WeightRowVector &x, typename moab::TempestOnlineMap::WeightColVector &result)
void	deterministicSparseMatTransposeVecMulClean (const typename moab::TempestOnlineMap::WeightMatrix &A, const typename moab::TempestOnlineMap::WeightRowVector &x, typename moab::TempestOnlineMap::WeightColVector &result)
void	deterministicSparseMatTransposeVecMulNative (const typename moab::TempestOnlineMap::WeightMatrix &A, const typename moab::TempestOnlineMap::WeightRowVector &x, typename moab::TempestOnlineMap::WeightColVector &result)

Function Documentation

deterministicSparseMatTransposeVecMul()

void deterministicSparseMatTransposeVecMul ( const typename moab::TempestOnlineMap::WeightMatrix &  A, const typename moab::TempestOnlineMap::WeightRowVector &  x, typename moab::TempestOnlineMap::WeightColVector &  result  )

inline

Definition at line 152 of file ApplyWeights.cpp.

{
    result.setZero();  // Ensure no uninitialized memory issues
 
    // Temporary storage for pairwise summation
    std::vector< std::set< double > > accumulators( A.cols() );
 
    // Iterate over A row-wise, but accumulate into result as if computing A^T * x
    for( int row = 0; row < A.outerSize(); ++row )
    {
        for( typename moab::TempestOnlineMap::WeightMatrix::InnerIterator it( A, row ); it; ++it )
        {
            accumulators[it.col()].insert( it.value() * x( row ) );
        }
    }
 
    // Compute final sum using pairwise summation for each entry
    for( int col = 0; col < A.cols(); ++col )
    {
        // result( col ) = pairwiseSum( accumulators[col] );
        result( col ) = pairwiseKahanSum( accumulators[col] );
    }
}

References pairwiseKahanSum().

deterministicSparseMatTransposeVecMulClean()

void deterministicSparseMatTransposeVecMulClean ( const typename moab::TempestOnlineMap::WeightMatrix &  A, const typename moab::TempestOnlineMap::WeightRowVector &  x, typename moab::TempestOnlineMap::WeightColVector &  result  )

inline

Definition at line 179 of file ApplyWeights.cpp.

{
    result.setZero();  // Ensure no uninitialized memory issues
 
    // Iterate over A row-wise, but accumulate into result as if computing A^T * x
    for( int row = 0; row < A.outerSize(); ++row )
    {
        for( typename moab::TempestOnlineMap::WeightMatrix::InnerIterator it( A, row ); it; ++it )
        {
            const double product = it.value() * x( row );  // Compute product
            result( it.col() ) += product;                 // Accumulate contributions to the corresponding row in A^T
        }
    }
}

References product().

Referenced by moab::TempestOnlineMap::ApplyWeights().

deterministicSparseMatTransposeVecMulNative()

void deterministicSparseMatTransposeVecMulNative ( const typename moab::TempestOnlineMap::WeightMatrix &  A, const typename moab::TempestOnlineMap::WeightRowVector &  x, typename moab::TempestOnlineMap::WeightColVector &  result  )

inline

Definition at line 197 of file ApplyWeights.cpp.

{
    result = A.adjoint() * x;  // Perform the adjoint.matrix-vector multiplication using Eigen3
}

deterministicSparseMatVecMul()

void deterministicSparseMatVecMul ( const typename moab::TempestOnlineMap::WeightMatrix &  A, const typename moab::TempestOnlineMap::WeightColVector &  x, typename moab::TempestOnlineMap::WeightRowVector &  result  )

inline

Definition at line 73 of file ApplyWeights.cpp.

{
    constexpr bool useKahanSum    = false;
    constexpr bool usePairwiseSum = false;
 
    result.setZero();  // Ensure no uninitialized memory issues
 
    // Iterate row-wise to enforce a fixed summation order
    for( int row = 0; row < A.outerSize(); ++row )
    {
        std::set< double > accumulators;
        for( typename moab::TempestOnlineMap::WeightMatrix::InnerIterator it( A, row ); it; ++it )
        {
            // accumulators contains the sorted values of the product: A(row, col) * x(col)
            accumulators.insert( it.value() * x( it.col() ) );
        }
        if( usePairwiseSum ) result( row ) = pairwiseSum( accumulators );
        if( useKahanSum ) result( row ) = pairwiseKahanSum( accumulators );
 
        if( !usePairwiseSum && !useKahanSum )
        {
            double sum = 0.0;
            for( double val : accumulators )
                sum += val;
            result( row ) = sum;
        }
    }
}

References pairwiseKahanSum(), pairwiseSum(), and moab::sum().

deterministicSparseMatVecMulClean()

void deterministicSparseMatVecMulClean ( const typename moab::TempestOnlineMap::WeightMatrix &  A, const typename moab::TempestOnlineMap::WeightColVector &  x, typename moab::TempestOnlineMap::WeightRowVector &  result  )

inline

Definition at line 127 of file ApplyWeights.cpp.

{
    result.setZero();  // Ensure no uninitialized memory issues
 
    // Iterate row-wise to enforce a fixed summation order
    for( int row = 0; row < A.outerSize(); ++row )
    {
        for( typename moab::TempestOnlineMap::WeightMatrix::InnerIterator it( A, row ); it; ++it )
        {
            const double product = it.value() * x( it.col() );  // Compute product
            result( it.row() ) += product;
        }
    }
}

References product().

Referenced by moab::TempestOnlineMap::ApplyWeights().

deterministicSparseMatVecMulKahan()

void deterministicSparseMatVecMulKahan ( const typename moab::TempestOnlineMap::WeightMatrix &  A, const typename moab::TempestOnlineMap::WeightColVector &  x, typename moab::TempestOnlineMap::WeightRowVector &  result  )

inline

Definition at line 106 of file ApplyWeights.cpp.

{
    result.setZero();  // Ensure no uninitialized memory issues
 
    // Iterate row-wise to enforce a fixed summation order
    for( int row = 0; row < A.outerSize(); ++row )
    {
        KahanSum kahan;
        for( typename moab::TempestOnlineMap::WeightMatrix::InnerIterator it( A, row ); it; ++it )
        {
            double product = it.value() * x( it.col() );  // Compute product
            kahan.add( product );
        }
 
        result( row ) = kahan.result();
    }
}

References KahanSum::add(), product(), and KahanSum::result().

deterministicSparseMatVecMulNative()

void deterministicSparseMatVecMulNative ( const typename moab::TempestOnlineMap::WeightMatrix &  A, const typename moab::TempestOnlineMap::WeightColVector &  x, typename moab::TempestOnlineMap::WeightRowVector &  result  )

inline

Definition at line 144 of file ApplyWeights.cpp.

{
    result = A * x;  // Perform the matrix-vector multiplication using Eigen3
}

pairwiseKahanSum()

double pairwiseKahanSum ( const std::set< double > &  sorted )

inline

Definition at line 59 of file ApplyWeights.cpp.

{
    if( sorted.empty() ) return 0.0;
    if( sorted.size() == 1 ) return *sorted.begin();
 
    // Accumulate pairwise to minimize rounding error
    // Apply pairwise summation with Kahan correction
    KahanSum kahan;
    for( double val : sorted )
        kahan.add( val );
    return kahan.result();
}

References KahanSum::add(), and KahanSum::result().

Referenced by deterministicSparseMatTransposeVecMul(), and deterministicSparseMatVecMul().

pairwiseSum()

double pairwiseSum ( const std::set< double > &  sorted )

inline

Definition at line 46 of file ApplyWeights.cpp.

{
    if( sorted.empty() ) return 0.0;
    if( sorted.size() == 1 ) return *sorted.begin();
 
    // Accumulate pairwise to minimize rounding error
    double sum = 0.0;
    for( double val : sorted )
        sum += val;
    return sum;
}

References moab::sum().

Referenced by deterministicSparseMatVecMul().