gemv

import mir.ndslice;
import mir.sparse;

auto slice = sparse!double(3, 5);
slice[] =
    [[ 0.0, 2.0,  3.0, 0.0, 0.0],
     [ 6.0, 0.0, 30.0, 8.0, 0.0],
     [ 6.0, 0.0, 30.0, 8.0, 0.0]];
auto alpha = 3.0;
auto a = slice.compress;
auto x =  [ 17.0, 19, 31, 3, 5].sliced;
auto beta = 2.0;
auto y = [1.0, 2, 3].sliced;
auto t = [131.0, 1056.0, 1056.0].sliced;
t[] *= alpha;
import mir.glas.l1: axpy;
axpy(beta, y, t);
gemv(alpha, a, x, beta, y);
assert(t == y);