Two alternatives to vex::multivector

mv_alt.cpp

#define VEXCL_SHOW_KERNELS
#define USE_PERMUTATION

#include <vexcl/vexcl.hpp>


int main() {
    vex::Context ctx(vex::Filter::Count(1));

    const size_t n = 5;

    vex::vector<double> x(ctx, 3 * n);
    auto X = vex::tag<0>(x);

#ifdef USE_PERMUTATION
    auto idx = vex::tag<1>( vex::element_index(0, n) );
    auto N   = vex::tag<2>( n );
    VEX_CONSTANT(two, 2);

    auto x0 = vex::permutation(idx            )(X);
    auto x1 = vex::permutation(idx + N        )(X);
    auto x2 = vex::permutation(idx + N * two())(X);
#else
    vex::slicer<2> slice( vex::extents[3][n] );

    auto x0 = slice[0](X);
    auto x1 = slice[1](X);
    auto x2 = slice[2](X);
#endif
    // write individual components:
    x0 = 1;
    x1 = 2;
    x2 = 3;

    // Do the fused call:
    vex::tie(x0, x1, x2) = std::tie(sin(x0), cos(x1), x1 - x0);
}