for( int i=0; i<MB; ++i){

for( int j=0; j<NB; ++j) {

block_computation(i, j);

}

}

auto beg = std::chrono::high_resolution_clock::now();

wavefront_seq();

auto end = std::chrono::high_resolution_clock::now();

return std::chrono::duration_cast<std::chrono::milliseconds>(end - beg);