gemm.cpp

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#define SHARK_USE_SIMD
#include <shark/LinAlg/BLAS/blas.h>
#include <shark/Core/Timer.h>
#include <iostream>
using namespace shark;
using namespace std;
 
template<class AMat, class BMat, class CMat>
double benchmark(
    blas::matrix_expression<AMat, blas::cpu_tag> const& A,
    blas::matrix_expression<BMat, blas::cpu_tag> const& B,
    blas::matrix_expression<CMat, blas::cpu_tag> & C
){
    double minTime = std::numeric_limits<double>::max();
    for(std::size_t i = 0; i != 10; ++i){
        Timer time;
        noalias(C) += prod(A,B);
        minTime = min(minTime,time.stop());
    }
    return (A().size1()*A().size2()*B().size2())/minTime/1024/1024;
}
 
int main(int argc, char **argv) {
    std::size_t size = 100;
    std::cout<<"Flops"<<std::endl;
    for(std::size_t iter = 0; iter != 5; ++iter){
        std::size_t middle = size;
        blas::matrix<double,blas::row_major> Arow(size,middle);
        for(std::size_t i = 0; i != size; ++i){
            for(std::size_t k = 0; k != middle; ++k){
                Arow(i,k)  = 0.1/size*i+0.1/size*k;
            }
        }
        
        blas::matrix<double,blas::row_major> Brow(middle,size);
        for(std::size_t k = 0; k != middle; ++k){
            for(std::size_t j = 0; j != size; ++j){
                Brow(k,j) = 0.1/size*j+0.1/size*k;
            }
        }
        blas::matrix<double,blas::column_major> Acol = Arow;
        blas::matrix<double,blas::column_major> Bcol = Brow;
        
        blas::matrix<double,blas::row_major> Crow(size,size,0.0);
        blas::matrix<double,blas::column_major> Ccol(size,size,0.0);
        std::cout<<size<<"\t row major results\t"<<benchmark(Arow,Brow,Crow)<<"\t"<< benchmark(Acol,Brow,Crow)
        <<"\t"<< benchmark(Arow,Bcol,Crow) <<"\t" <<benchmark(Acol,Bcol,Crow) <<std::endl;
        std::cout<<size<<"\t column major results\t"<<benchmark(Arow,Brow,Ccol)<<"\t"<< benchmark(Acol,Brow,Ccol)
        <<"\t"<< benchmark(Arow,Bcol,Ccol) <<"\t" <<benchmark(Acol,Bcol,Ccol) <<std::endl;
        size *=2;
    }
}