Function gfor

test/convolve.cpp:627–627

    array K = randu(3, 3);

    gfor(seq ii, 3) { B(span, span, ii) = convolve2(A(span, span, ii), K); }

    for (int ii = 0; ii < 3; ii++) {
        array c_ii = convolve2(A(span, span, ii), K);