Function gfor

test/approx2.cpp:366–370

    array outGFOR(pos.dims());
    gfor(seq i, pos.dims(2)) {
        outGFOR(span, span, i) =
            approx2(input(span, span, i), pos(span, span, i),
                    qos(span, span, i), AF_INTERP_NEAREST);
    }

    ASSERT_NEAR(0, sum<float>(abs(outBatch - outSerial)), 1e-3);
    ASSERT_NEAR(0, sum<float>(abs(outBatch - outGFOR)), 1e-3);