private void bitrv216(float[] a, int offa) {
        float x1r, x1i, x2r, x2i, x3r, x3i, x4r, x4i, x5r, x5i, x7r, x7i, x8r, x8i, x10r, x10i, x11r, x11i, x12r, x12i, x13r, x13i, x14r, x14i;

        x1r = a[offa + 2];
        x1i = a[offa + 3];
        x2r = a[offa + 4];
        x2i = a[offa + 5];
        x3r = a[offa + 6];
        x3i = a[offa + 7];
        x4r = a[offa + 8];
        x4i = a[offa + 9];
        x5r = a[offa + 10];
        x5i = a[offa + 11];
        x7r = a[offa + 14];
        x7i = a[offa + 15];
        x8r = a[offa + 16];
        x8i = a[offa + 17];
        x10r = a[offa + 20];
        x10i = a[offa + 21];
        x11r = a[offa + 22];
        x11i = a[offa + 23];
        x12r = a[offa + 24];
        x12i = a[offa + 25];
        x13r = a[offa + 26];
        x13i = a[offa + 27];
        x14r = a[offa + 28];
        x14i = a[offa + 29];
        a[offa + 2] = x8r;
        a[offa + 3] = x8i;
        a[offa + 4] = x4r;
        a[offa + 5] = x4i;
        a[offa + 6] = x12r;
        a[offa + 7] = x12i;
        a[offa + 8] = x2r;
        a[offa + 9] = x2i;
        a[offa + 10] = x10r;
        a[offa + 11] = x10i;
        a[offa + 14] = x14r;
        a[offa + 15] = x14i;
        a[offa + 16] = x1r;
        a[offa + 17] = x1i;
        a[offa + 20] = x5r;
        a[offa + 21] = x5i;
        a[offa + 22] = x13r;
        a[offa + 23] = x13i;
        a[offa + 24] = x3r;
        a[offa + 25] = x3i;
        a[offa + 26] = x11r;
        a[offa + 27] = x11i;
        a[offa + 28] = x7r;
        a[offa + 29] = x7i;
    }