diff options
Diffstat (limited to 'externals/grill/fftease/src/fft4.c')
-rw-r--r-- | externals/grill/fftease/src/fft4.c | 340 |
1 files changed, 0 insertions, 340 deletions
diff --git a/externals/grill/fftease/src/fft4.c b/externals/grill/fftease/src/fft4.c deleted file mode 100644 index 70127b47..00000000 --- a/externals/grill/fftease/src/fft4.c +++ /dev/null @@ -1,340 +0,0 @@ -/* - * This file is part of the pv-lib - * - * The pv-lib can be used by everyone as desired - * - * (c) Eric Lyon and Christopher Penrose - * - */ - -#include <math.h> -#include "pv.h" - -static void bitrv2(int n, int *ip, float *a); -static void cftsub(int n, float *a, float *w); -static void rftsub(int n, float *a, int nc, float *c); -static void makewt(int nw, int *ip, float *w); -static void makect(int nc, int *ip, float *c); - -void init_rdft(int n, int *ip, float *w) -{ - - int nw, - nc; - - nw = n >> 2; - makewt(nw, ip, w); - - nc = n >> 2; - makect(nc, ip, w + nw); - - return; -} - - -void pv_rdft(int n, int isgn, float *a, int *ip, float *w) -{ - - int j, - nw, - nc; - - float xi; - - nw = ip[0]; - nc = ip[1]; - - if (isgn < 0) { - a[1] = 0.5 * (a[1] - a[0]); - a[0] += a[1]; - - for (j = 3; j <= n - 1; j += 2) { - a[j] = -a[j]; - } - - if (n > 4) { - rftsub(n, a, nc, w + nw); - bitrv2(n, ip + 2, a); - } - - cftsub(n, a, w); - - for (j = 1; j < n; j += 2) { - a[j] = -a[j]; - } - } - - else { - - if (n > 4) { - bitrv2(n, ip + 2, a); - } - - cftsub(n, a, w); - - if (n > 4) { - rftsub(n, a, nc, w + nw); - } - - xi = a[0] - a[1]; - a[0] += a[1]; - a[1] = xi; - } -} - - -static void bitrv2(int n, int *ip, float *a) -{ - int j, j1, k, k1, l, m, m2; - float xr, xi; - - ip[0] = 0; - l = n; - m = 1; - - while ((m << 2) < l) { - l >>= 1; - for (j = 0; j < m; j++) { - ip[m + j] = ip[j] + l; - } - m <<= 1; - } - - if ((m << 2) > l) { - - for (k = 1; k < m; k++) { - - for (j = 0; j <= k - 1; j++) { - j1 = (j << 1) + ip[k]; - k1 = (k << 1) + ip[j]; - xr = a[j1]; - xi = a[j1 + 1]; - a[j1] = a[k1]; - a[j1 + 1] = a[k1 + 1]; - a[k1] = xr; - a[k1 + 1] = xi; - } - } - } - - else { - m2 = m << 1; - - for (k = 1; k < m; k++) { - - for (j = 0; j < k; j++) { - j1 = (j << 1) + ip[k]; - k1 = (k << 1) + ip[j]; - xr = a[j1]; - xi = a[j1 + 1]; - a[j1] = a[k1]; - a[j1 + 1] = a[k1 + 1]; - a[k1] = xr; - a[k1 + 1] = xi; - j1 += m2; - k1 += m2; - xr = a[j1]; - xi = a[j1 + 1]; - a[j1] = a[k1]; - a[j1 + 1] = a[k1 + 1]; - a[k1] = xr; - a[k1 + 1] = xi; - } - } - } -} - - -static void cftsub(int n, float *a, float *w) -{ - int j, j1, j2, j3, k, k1, ks, l, m; - float wk1r, wk1i, wk2r, wk2i, wk3r, wk3i; - float x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i; - - l = 2; - - while ((l << 1) < n) { - m = l << 2; - - for (j = 0; j <= l - 2; j += 2) { - j1 = j + l; - j2 = j1 + l; - j3 = j2 + l; - x0r = a[j] + a[j1]; - x0i = a[j + 1] + a[j1 + 1]; - x1r = a[j] - a[j1]; - x1i = a[j + 1] - a[j1 + 1]; - x2r = a[j2] + a[j3]; - x2i = a[j2 + 1] + a[j3 + 1]; - x3r = a[j2] - a[j3]; - x3i = a[j2 + 1] - a[j3 + 1]; - a[j] = x0r + x2r; - a[j + 1] = x0i + x2i; - a[j2] = x0r - x2r; - a[j2 + 1] = x0i - x2i; - a[j1] = x1r - x3i; - a[j1 + 1] = x1i + x3r; - a[j3] = x1r + x3i; - a[j3 + 1] = x1i - x3r; - } - - if (m < n) { - wk1r = w[2]; - - for (j = m; j <= l + m - 2; j += 2) { - j1 = j + l; - j2 = j1 + l; - j3 = j2 + l; - x0r = a[j] + a[j1]; - x0i = a[j + 1] + a[j1 + 1]; - x1r = a[j] - a[j1]; - x1i = a[j + 1] - a[j1 + 1]; - x2r = a[j2] + a[j3]; - x2i = a[j2 + 1] + a[j3 + 1]; - x3r = a[j2] - a[j3]; - x3i = a[j2 + 1] - a[j3 + 1]; - a[j] = x0r + x2r; - a[j + 1] = x0i + x2i; - a[j2] = x2i - x0i; - a[j2 + 1] = x0r - x2r; - x0r = x1r - x3i; - x0i = x1i + x3r; - a[j1] = wk1r * (x0r - x0i); - a[j1 + 1] = wk1r * (x0r + x0i); - x0r = x3i + x1r; - x0i = x3r - x1i; - a[j3] = wk1r * (x0i - x0r); - a[j3 + 1] = wk1r * (x0i + x0r); - } - - k1 = 1; - ks = -1; - - for (k = (m << 1); k <= n - m; k += m) { - k1++; - ks = -ks; - wk1r = w[k1 << 1]; - wk1i = w[(k1 << 1) + 1]; - wk2r = ks * w[k1]; - wk2i = w[k1 + ks]; - wk3r = wk1r - 2 * wk2i * wk1i; - wk3i = 2 * wk2i * wk1r - wk1i; - - for (j = k; j <= l + k - 2; j += 2) { - j1 = j + l; - j2 = j1 + l; - j3 = j2 + l; - x0r = a[j] + a[j1]; - x0i = a[j + 1] + a[j1 + 1]; - x1r = a[j] - a[j1]; - x1i = a[j + 1] - a[j1 + 1]; - x2r = a[j2] + a[j3]; - x2i = a[j2 + 1] + a[j3 + 1]; - x3r = a[j2] - a[j3]; - x3i = a[j2 + 1] - a[j3 + 1]; - a[j] = x0r + x2r; - a[j + 1] = x0i + x2i; - x0r -= x2r; - x0i -= x2i; - a[j2] = wk2r * x0r - wk2i * x0i; - a[j2 + 1] = wk2r * x0i + wk2i * x0r; - x0r = x1r - x3i; - x0i = x1i + x3r; - a[j1] = wk1r * x0r - wk1i * x0i; - a[j1 + 1] = wk1r * x0i + wk1i * x0r; - x0r = x1r + x3i; - x0i = x1i - x3r; - a[j3] = wk3r * x0r - wk3i * x0i; - a[j3 + 1] = wk3r * x0i + wk3i * x0r; - } - } - } - - l = m; - } - - if (l < n) { - - for (j = 0; j <= l - 2; j += 2) { - j1 = j + l; - x0r = a[j] - a[j1]; - x0i = a[j + 1] - a[j1 + 1]; - a[j] += a[j1]; - a[j + 1] += a[j1 + 1]; - a[j1] = x0r; - a[j1 + 1] = x0i; - } - } -} - - -static void rftsub(int n, float *a, int nc, float *c) -{ - int j, k, kk, ks; - float wkr, wki, xr, xi, yr, yi; - - ks = (nc << 2) / n; - kk = 0; - - for (k = (n >> 1) - 2; k >= 2; k -= 2) { - j = n - k; - kk += ks; - wkr = 0.5 - c[kk]; - wki = c[nc - kk]; - xr = a[k] - a[j]; - xi = a[k + 1] + a[j + 1]; - yr = wkr * xr - wki * xi; - yi = wkr * xi + wki * xr; - a[k] -= yr; - a[k + 1] -= yi; - a[j] += yr; - a[j + 1] -= yi; - } -} - - -static void makewt(int nw, int *ip, float *w) -{ - int nwh, j; - float delta, x, y; - - ip[0] = nw; - ip[1] = 1; - if (nw > 2) { - nwh = nw >> 1; - delta = atan(1.0) / nwh; - w[0] = 1; - w[1] = 0; - w[nwh] = cos(delta * nwh); - w[nwh + 1] = w[nwh]; - for (j = 2; j <= nwh - 2; j += 2) { - x = cos(delta * j); - y = sin(delta * j); - w[j] = x; - w[j + 1] = y; - w[nw - j] = y; - w[nw - j + 1] = x; - } - bitrv2(nw, ip + 2, w); - } -} - - -static void makect(int nc, int *ip, float *c) -{ - int nch, j; - float delta; - - ip[1] = nc; - if (nc > 1) { - nch = nc >> 1; - delta = atan(1.0) / nch; - c[0] = 0.5; - c[nch] = 0.5 * cos(delta * nch); - for (j = 1; j <= nch - 1; j++) { - c[j] = 0.5 * cos(delta * j); - c[nc - j] = 0.5 * sin(delta * j); - } - } -} - |