fftsg.cpp.svn-base

ffshow源码

                        a[j3] = wk3r * x0r + wk3i * x0i;
                        a[j3 + 1] = wk3r * x0i - wk3i * x0r;
                        x0r = y1r + y3i;
                        x0i = y1i - y3r;
                        a[j3 + 2] = wd3r * x0r + wd3i * x0i;
                        a[j3 + 3] = wd3r * x0i - wd3i * x0r;
                        j0 = m - j;
                        j1 = j0 + m;
                        j2 = j1 + m;
                        j3 = j2 + m;
                        x0r = a[j0] + a[j2];
                        x0i = a[j0 + 1] + a[j2 + 1];
                        x1r = a[j0] - a[j2];
                        x1i = a[j0 + 1] - a[j2 + 1];
                        y0r = a[j0 - 2] + a[j2 - 2];
                        y0i = a[j0 - 1] + a[j2 - 1];
                        y1r = a[j0 - 2] - a[j2 - 2];
                        y1i = a[j0 - 1] - a[j2 - 1];
                        x2r = a[j1] + a[j3];
                        x2i = a[j1 + 1] + a[j3 + 1];
                        x3r = a[j1] - a[j3];
                        x3i = a[j1 + 1] - a[j3 + 1];
                        y2r = a[j1 - 2] + a[j3 - 2];
                        y2i = a[j1 - 1] + a[j3 - 1];
                        y3r = a[j1 - 2] - a[j3 - 2];
                        y3i = a[j1 - 1] - a[j3 - 1];
                        a[j0] = x0r + x2r;
                        a[j0 + 1] = x0i + x2i;
                        a[j0 - 2] = y0r + y2r;
                        a[j0 - 1] = y0i + y2i;
                        a[j1] = x0r - x2r;
                        a[j1 + 1] = x0i - x2i;
                        a[j1 - 2] = y0r - y2r;
                        a[j1 - 1] = y0i - y2i;
                        x0r = x1r - x3i;
                        x0i = x1i + x3r;
                        a[j2] = wk1i * x0r - wk1r * x0i;
                        a[j2 + 1] = wk1i * x0i + wk1r * x0r;
                        x0r = y1r - y3i;
                        x0i = y1i + y3r;
                        a[j2 - 2] = wd1i * x0r - wd1r * x0i;
                        a[j2 - 1] = wd1i * x0i + wd1r * x0r;
                        x0r = x1r + x3i;
                        x0i = x1i - x3r;
                        a[j3] = wk3i * x0r + wk3r * x0i;
                        a[j3 + 1] = wk3i * x0i - wk3r * x0r;
                        x0r = y1r + y3i;
                        x0i = y1i - y3r;
                        a[j3 - 2] = wd3i * x0r + wd3r * x0i;
                        a[j3 - 1] = wd3i * x0i - wd3r * x0r;
                }
                wk1r = csc1 * (wd1r + wn4r);
                wk1i = csc1 * (wd1i + wn4r);
                wk3r = csc3 * (wd3r - wn4r);
                wk3i = csc3 * (wd3i - wn4r);
                j0 = mh;
                j1 = j0 + m;
                j2 = j1 + m;
                j3 = j2 + m;
                x0r = a[j0 - 2] + a[j2 - 2];
                x0i = a[j0 - 1] + a[j2 - 1];
                x1r = a[j0 - 2] - a[j2 - 2];
                x1i = a[j0 - 1] - a[j2 - 1];
                x2r = a[j1 - 2] + a[j3 - 2];
                x2i = a[j1 - 1] + a[j3 - 1];
                x3r = a[j1 - 2] - a[j3 - 2];
                x3i = a[j1 - 1] - a[j3 - 1];
                a[j0 - 2] = x0r + x2r;
                a[j0 - 1] = x0i + x2i;
                a[j1 - 2] = x0r - x2r;
                a[j1 - 1] = x0i - x2i;
                x0r = x1r - x3i;
                x0i = x1i + x3r;
                a[j2 - 2] = wk1r * x0r - wk1i * x0i;
                a[j2 - 1] = wk1r * x0i + wk1i * x0r;
                x0r = x1r + x3i;
                x0i = x1i - x3r;
                a[j3 - 2] = wk3r * x0r + wk3i * x0i;
                a[j3 - 1] = wk3r * x0i - wk3i * x0r;
                x0r = a[j0] + a[j2];
                x0i = a[j0 + 1] + a[j2 + 1];
                x1r = a[j0] - a[j2];
                x1i = a[j0 + 1] - a[j2 + 1];
                x2r = a[j1] + a[j3];
                x2i = a[j1 + 1] + a[j3 + 1];
                x3r = a[j1] - a[j3];
                x3i = a[j1 + 1] - a[j3 + 1];
                a[j0] = x0r + x2r;
                a[j0 + 1] = x0i + x2i;
                a[j1] = x0r - x2r;
                a[j1 + 1] = x0i - x2i;
                x0r = x1r - x3i;
                x0i = x1i + x3r;
                a[j2] = wn4r * (x0r - x0i);
                a[j2 + 1] = wn4r * (x0i + x0r);
                x0r = x1r + x3i;
                x0i = x1i - x3r;
                a[j3] = -wn4r * (x0r + x0i);
                a[j3 + 1] = -wn4r * (x0i - x0r);
                x0r = a[j0 + 2] + a[j2 + 2];
                x0i = a[j0 + 3] + a[j2 + 3];
                x1r = a[j0 + 2] - a[j2 + 2];
                x1i = a[j0 + 3] - a[j2 + 3];
                x2r = a[j1 + 2] + a[j3 + 2];
                x2i = a[j1 + 3] + a[j3 + 3];
                x3r = a[j1 + 2] - a[j3 + 2];
                x3i = a[j1 + 3] - a[j3 + 3];
                a[j0 + 2] = x0r + x2r;
                a[j0 + 3] = x0i + x2i;
                a[j1 + 2] = x0r - x2r;
                a[j1 + 3] = x0i - x2i;
                x0r = x1r - x3i;
                x0i = x1i + x3r;
                a[j2 + 2] = wk1i * x0r - wk1r * x0i;
                a[j2 + 3] = wk1i * x0i + wk1r * x0r;
                x0r = x1r + x3i;
                x0i = x1i - x3r;
                a[j3 + 2] = wk3i * x0r + wk3r * x0i;
                a[j3 + 3] = wk3i * x0i - wk3r * x0r;
        }


        static void cftb1st(int n, REAL *a, REAL *w)
        {
                int j, j0, j1, j2, j3, k, m, mh;
                REAL wn4r, csc1, csc3, wk1r, wk1i, wk3r, wk3i, 
                        wd1r, wd1i, wd3r, wd3i;
                REAL x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i, 
                        y0r, y0i, y1r, y1i, y2r, y2i, y3r, y3i;
    
                mh = n >> 3;
                m = 2 * mh;
                j1 = m;
                j2 = j1 + m;
                j3 = j2 + m;
                x0r = a[0] + a[j2];
                x0i = -a[1] - a[j2 + 1];
                x1r = a[0] - a[j2];
                x1i = -a[1] + a[j2 + 1];
                x2r = a[j1] + a[j3];
                x2i = a[j1 + 1] + a[j3 + 1];
                x3r = a[j1] - a[j3];
                x3i = a[j1 + 1] - a[j3 + 1];
                a[0] = x0r + x2r;
                a[1] = x0i - x2i;
                a[j1] = x0r - x2r;
                a[j1 + 1] = x0i + x2i;
                a[j2] = x1r + x3i;
                a[j2 + 1] = x1i + x3r;
                a[j3] = x1r - x3i;
                a[j3 + 1] = x1i - x3r;
                wn4r = w[1];
                csc1 = w[2];
                csc3 = w[3];
                wd1r = 1;
                wd1i = 0;
                wd3r = 1;
                wd3i = 0;
                k = 0;
                for (j = 2; j < mh - 2; j += 4) {
                        k += 4;
                        wk1r = csc1 * (wd1r + w[k]);
                        wk1i = csc1 * (wd1i + w[k + 1]);
                        wk3r = csc3 * (wd3r + w[k + 2]);
                        wk3i = csc3 * (wd3i - w[k + 3]);
                        wd1r = w[k];
                        wd1i = w[k + 1];
                        wd3r = w[k + 2];
                        wd3i = -w[k + 3];
                        j1 = j + m;
                        j2 = j1 + m;
                        j3 = j2 + m;
                        x0r = a[j] + a[j2];
                        x0i = -a[j + 1] - a[j2 + 1];
                        x1r = a[j] - a[j2];
                        x1i = -a[j + 1] + a[j2 + 1];
                        y0r = a[j + 2] + a[j2 + 2];
                        y0i = -a[j + 3] - a[j2 + 3];
                        y1r = a[j + 2] - a[j2 + 2];
                        y1i = -a[j + 3] + a[j2 + 3];
                        x2r = a[j1] + a[j3];
                        x2i = a[j1 + 1] + a[j3 + 1];
                        x3r = a[j1] - a[j3];
                        x3i = a[j1 + 1] - a[j3 + 1];
                        y2r = a[j1 + 2] + a[j3 + 2];
                        y2i = a[j1 + 3] + a[j3 + 3];
                        y3r = a[j1 + 2] - a[j3 + 2];
                        y3i = a[j1 + 3] - a[j3 + 3];
                        a[j] = x0r + x2r;
                        a[j + 1] = x0i - x2i;
                        a[j + 2] = y0r + y2r;
                        a[j + 3] = y0i - y2i;
                        a[j1] = x0r - x2r;
                        a[j1 + 1] = x0i + x2i;
                        a[j1 + 2] = y0r - y2r;
                        a[j1 + 3] = y0i + y2i;
                        x0r = x1r + x3i;
                        x0i = x1i + x3r;
                        a[j2] = wk1r * x0r - wk1i * x0i;
                        a[j2 + 1] = wk1r * x0i + wk1i * x0r;
                        x0r = y1r + y3i;
                        x0i = y1i + y3r;
                        a[j2 + 2] = wd1r * x0r - wd1i * x0i;
                        a[j2 + 3] = wd1r * x0i + wd1i * x0r;
                        x0r = x1r - x3i;
                        x0i = x1i - x3r;
                        a[j3] = wk3r * x0r + wk3i * x0i;
                        a[j3 + 1] = wk3r * x0i - wk3i * x0r;
                        x0r = y1r - y3i;
                        x0i = y1i - y3r;
                        a[j3 + 2] = wd3r * x0r + wd3i * x0i;
                        a[j3 + 3] = wd3r * x0i - wd3i * x0r;
                        j0 = m - j;
                        j1 = j0 + m;
                        j2 = j1 + m;
                        j3 = j2 + m;
                        x0r = a[j0] + a[j2];
                        x0i = -a[j0 + 1] - a[j2 + 1];
                        x1r = a[j0] - a[j2];
                        x1i = -a[j0 + 1] + a[j2 + 1];
                        y0r = a[j0 - 2] + a[j2 - 2];
                        y0i = -a[j0 - 1] - a[j2 - 1];
                        y1r = a[j0 - 2] - a[j2 - 2];
                        y1i = -a[j0 - 1] + a[j2 - 1];
                        x2r = a[j1] + a[j3];
                        x2i = a[j1 + 1] + a[j3 + 1];
                        x3r = a[j1] - a[j3];
                        x3i = a[j1 + 1] - a[j3 + 1];
                        y2r = a[j1 - 2] + a[j3 - 2];
                        y2i = a[j1 - 1] + a[j3 - 1];
                        y3r = a[j1 - 2] - a[j3 - 2];
                        y3i = a[j1 - 1] - a[j3 - 1];
                        a[j0] = x0r + x2r;
                        a[j0 + 1] = x0i - x2i;
                        a[j0 - 2] = y0r + y2r;
                        a[j0 - 1] = y0i - y2i;
                        a[j1] = x0r - x2r;
                        a[j1 + 1] = x0i + x2i;
                        a[j1 - 2] = y0r - y2r;
                        a[j1 - 1] = y0i + y2i;
                        x0r = x1r + x3i;
                        x0i = x1i + x3r;
                        a[j2] = wk1i * x0r - wk1r * x0i;
                        a[j2 + 1] = wk1i * x0i + wk1r * x0r;
                        x0r = y1r + y3i;
                        x0i = y1i + y3r;
                        a[j2 - 2] = wd1i * x0r - wd1r * x0i;
                        a[j2 - 1] = wd1i * x0i + wd1r * x0r;
                        x0r = x1r - x3i;
                        x0i = x1i - x3r;
                        a[j3] = wk3i * x0r + wk3r * x0i;
                        a[j3 + 1] = wk3i * x0i - wk3r * x0r;
                        x0r = y1r - y3i;
                        x0i = y1i - y3r;
                        a[j3 - 2] = wd3i * x0r + wd3r * x0i;
                        a[j3 - 1] = wd3i * x0i - wd3r * x0r;
                }
                wk1r = csc1 * (wd1r + wn4r);
                wk1i = csc1 * (wd1i + wn4r);
                wk3r = csc3 * (wd3r - wn4r);
                wk3i = csc3 * (wd3i - wn4r);
                j0 = mh;
                j1 = j0 + m;
                j2 = j1 + m;
                j3 = j2 + m;
                x0r = a[j0 - 2] + a[j2 - 2];
                x0i = -a[j0 - 1] - a[j2 - 1];
                x1r = a[j0 - 2] - a[j2 - 2];
                x1i = -a[j0 - 1] + a[j2 - 1];
                x2r = a[j1 - 2] + a[j3 - 2];
                x2i = a[j1 - 1] + a[j3 - 1];
                x3r = a[j1 - 2] - a[j3 - 2];
                x3i = a[j1 - 1] - a[j3 - 1];
                a[j0 - 2] = x0r + x2r;
                a[j0 - 1] = x0i - x2i;
                a[j1 - 2] = x0r - x2r;
                a[j1 - 1] = x0i + x2i;
                x0r = x1r + x3i;
                x0i = x1i + x3r;
                a[j2 - 2] = wk1r * x0r - wk1i * x0i;
                a[j2 - 1] = wk1r * x0i + wk1i * x0r;
                x0r = x1r - x3i;
                x0i = x1i - x3r;
                a[j3 - 2] = wk3r * x0r + wk3i * x0i;
                a[j3 - 1] = wk3r * x0i - wk3i * x0r;
                x0r = a[j0] + a[j2];
                x0i = -a[j0 + 1] - a[j2 + 1];
                x1r = a[j0] - a[j2];
                x1i = -a[j0 + 1] + a[j2 + 1];
                x2r = a[j1] + a[j3];
                x2i = a[j1 + 1] + a[j3 + 1];
                x3r = a[j1] - a[j3];
                x3i = a[j1 + 1] - a[j3 + 1];
                a[j0] = x0r + x2r;
                a[j0 + 1] = x0i - x2i;
                a[j1] = x0r - x2r;
                a[j1 + 1] = x0i + x2i;
                x0r = x1r + x3i;
                x0i = x1i + x3r;
                a[j2] = wn4r * (x0r - x0i);
                a[j2 + 1] = wn4r * (x0i + x0r);
                x0r = x1r - x3i;
                x0i = x1i - x3r;