- /*
- Fast Fourier/Cosine/Sine Transform by T. Ooura
- This source file is created by extracting the neccesary part from a file
- "fft4g.c" packed in "fft.lzh".
- --------------------------------------------------------------
- Copyright:
- Copyright(C) 1996-1999 Takuya OOURA
- email: ooura@mmm.t.u-tokyo.ac.jp
- download: http://momonga.t.u-tokyo.ac.jp/~ooura/fft.html
- --------------------------------------------------------------
- dimension :one
- data length :power of 2
- decimation :frequency
- radix :4, 2
- data :inplace
- table :use
- -------- Real DFT / Inverse of Real DFT --------
- [definition]
- <case1> RDFT
- R[k] = sum_j=0^n-1 a[j]*cos(2*pi*j*k/n), 0<=k<=n/2
- I[k] = sum_j=0^n-1 a[j]*sin(2*pi*j*k/n), 0<k<n/2
- <case2> IRDFT (excluding scale)
- a[k] = (R[0] + R[n/2]*cos(pi*k))/2 +
- sum_j=1^n/2-1 R[j]*cos(2*pi*j*k/n) +
- sum_j=1^n/2-1 I[j]*sin(2*pi*j*k/n), 0<=k<n
- [usage]
- <case1>
- ip[0] = 0; // first time only
- rdft(n, 1, a, ip, w);
- <case2>
- ip[0] = 0; // first time only
- rdft(n, -1, a, ip, w);
- [parameters]
- n :data length (int)
- n >= 2, n = power of 2
- a[0...n-1] :input/output data (double *)
- <case1>
- output data
- a[2*k] = R[k], 0<=k<n/2
- a[2*k+1] = I[k], 0<k<n/2
- a[1] = R[n/2]
- <case2>
- input data
- a[2*j] = R[j], 0<=j<n/2
- a[2*j+1] = I[j], 0<j<n/2
- a[1] = R[n/2]
- ip[0...*] :work area for bit reversal (int *)
- length of ip >= 2+sqrt(n/2)
- strictly,
- length of ip >=
- 2+(1<<(int)(log(n/2+0.5)/log(2))/2).
- ip[0],ip[1] are pointers of the cos/sin table.
- w[0...n/2-1] :cos/sin table (double *)
- w[],ip[] are initialized if ip[0] == 0.
- [remark]
- Inverse of
- rdft(n, 1, a, ip, w);
- is
- rdft(n, -1, a, ip, w);
- for (j = 0; j <= n - 1; j++) {
- a[j] *= 2.0 / n;
- }
- .
- */
- #ifndef SN_H
- #include "sn.h"
- #endif
-
- void rdft(int n, int isgn, fftType *a, int *ip, fftType *w);
- void makect(int nc, int *ip, fftType *c);
- void makewt(int nw, int *ip, fftType *w);
- void bitrv2(int n, int *ip, fftType *a);
- void cftfsub(int n, fftType *a, fftType *w);
- void cftbsub(int n, fftType *a, fftType *w);
- void cftmdl(int n, int l, fftType *a, fftType *w);
- void cft1st(int n, fftType *a, fftType *w);
- void rftfsub(int n, fftType *a, int nc, fftType *c);
- void rftbsub(int n, fftType *a, int nc, fftType *c);
-
- void rdft(int n, int isgn, fftType *a, int *ip, fftType *w)
- {
- int nw, nc;
- fftType xi;
-
- nw = ip[0];
- if (n > (nw << 2)) {
- nw = n >> 2;
- makewt(nw, ip, w);
- }
- nc = ip[1];
- if (n > (nc << 2)) {
- nc = n >> 2;
- makect(nc, ip, w + nw);
- }
- if (isgn >= 0) {
- if (n > 4) {
- bitrv2(n, ip + 2, a);
- cftfsub(n, a, w);
- rftfsub(n, a, nc, w + nw);
- } else if (n == 4) {
- cftfsub(n, a, w);
- }
- xi = a[0] - a[1];
- a[0] += a[1];
- a[1] = xi;
- } else {
- a[1] = 0.5 * (a[0] - a[1]);
- a[0] -= a[1];
- if (n > 4) {
- rftbsub(n, a, nc, w + nw);
- bitrv2(n, ip + 2, a);
- cftbsub(n, a, w);
- } else if (n == 4) {
- cftfsub(n, a, w);
- }
- }
- }
- void bitrv2(int n, int *ip, fftType *a)
- {
- int j, j1, k, k1, l, m, m2;
- fftType xr, xi, yr, yi;
-
- ip[0] = 0;
- l = n;
- m = 1;
- while ((m << 3) < l) {
- l >>= 1;
- for (j = 0; j < m; j++) {
- ip[m + j] = ip[j] + l;
- }
- m <<= 1;
- }
- m2 = 2 * m;
- if ((m << 3) == l) {
- for (k = 0; k < m; k++) {
- for (j = 0; j < k; j++) {
- j1 = 2 * j + ip[k];
- k1 = 2 * k + ip[j];
- xr = a[j1];
- xi = a[j1 + 1];
- yr = a[k1];
- yi = a[k1 + 1];
- a[j1] = yr;
- a[j1 + 1] = yi;
- a[k1] = xr;
- a[k1 + 1] = xi;
- j1 += m2;
- k1 += 2 * m2;
- xr = a[j1];
- xi = a[j1 + 1];
- yr = a[k1];
- yi = a[k1 + 1];
- a[j1] = yr;
- a[j1 + 1] = yi;
- a[k1] = xr;
- a[k1 + 1] = xi;
- j1 += m2;
- k1 -= m2;
- xr = a[j1];
- xi = a[j1 + 1];
- yr = a[k1];
- yi = a[k1 + 1];
- a[j1] = yr;
- a[j1 + 1] = yi;
- a[k1] = xr;
- a[k1 + 1] = xi;
- j1 += m2;
- k1 += 2 * m2;
- xr = a[j1];
- xi = a[j1 + 1];
- yr = a[k1];
- yi = a[k1 + 1];
- a[j1] = yr;
- a[j1 + 1] = yi;
- a[k1] = xr;
- a[k1 + 1] = xi;
- }
- j1 = 2 * k + m2 + ip[k];
- k1 = j1 + m2;
- xr = a[j1];
- xi = a[j1 + 1];
- yr = a[k1];
- yi = a[k1 + 1];
- a[j1] = yr;
- a[j1 + 1] = yi;
- a[k1] = xr;
- a[k1 + 1] = xi;
- }
- } else {
- for (k = 1; k < m; k++) {
- for (j = 0; j < k; j++) {
- j1 = 2 * j + ip[k];
- k1 = 2 * k + ip[j];
- xr = a[j1];
- xi = a[j1 + 1];
- yr = a[k1];
- yi = a[k1 + 1];
- a[j1] = yr;
- a[j1 + 1] = yi;
- a[k1] = xr;
- a[k1 + 1] = xi;
- j1 += m2;
- k1 += m2;
- xr = a[j1];
- xi = a[j1 + 1];
- yr = a[k1];
- yi = a[k1 + 1];
- a[j1] = yr;
- a[j1 + 1] = yi;
- a[k1] = xr;
- a[k1 + 1] = xi;
- }
- }
- }
- }
- #if USES_SIN_COS_TABLE == 0
- /// Ooura's version
- void makewt(int nw, int *ip, fftType *w)
- {
- int j, nwh;
- fftType delta, x, y;
- ip[0] = nw;
- ip[1] = 1;
- if (nw > 2) {
- nwh = nw >> 1; // nwh =1024, 2048, ... 2^k
- // delta = atan(1.0) / nwh;
- delta = fftM_PI_4 / nwh;
- w[0] = 1;
- w[1] = 0;
- w[nwh] = fftCos(delta * nwh);
- w[nwh + 1] = w[nwh];
- if (nwh > 2) {
- for (j = 2; j < nwh; j += 2) {
- x = fftCos(delta * j);
- y = fftSin(delta * j);
- w[j] = x;
- w[j + 1] = y;
- w[nw - j] = y;
- w[nw - j + 1] = x;
- }
- bitrv2(nw, ip + 2, w);
- }
- }
- }
- void makect(int nc, int *ip, fftType *c)
- {
- int j, nch;
- fftType delta;
-
- ip[1] = nc;
- if (nc > 1) {
- nch = nc >> 1; // nch = 1024, 2048,...
- delta = fftM_PI_4/nch; // atan(1.0) / nch;
- c[0] = fftCos(delta * nch);
- c[nch] = 0.5 * c[0];
- for (j = 1; j < nch; j++) {
- c[j] = 0.5 * fftCos(delta * j);
- c[nc - j] = 0.5 * fftSin(delta * j);
- }
- }
- }
- #else
- void makewt(int nw, int *ip, fftType *w)
- {
- // int j, nwh;
- long j, nwh;
- // fftType delta, x, y;
- fftType x, y;
- ip[0] = nw;
- ip[1] = 1;
- if (nw > 2) {
- nwh = nw >> 1;
- // delta = atan(1.0) / nwh;
- // delta = fftM_PI_4 / nwh;
- w[0] = 1;
- w[1] = 0;
- w[nwh] = fftCosR(nwh, nwh);
- // w[nwh] = fftCos(delta * nwh);
- w[nwh + 1] = w[nwh];
- if (nwh > 2) {
- for (j = 2; j < nwh; j += 2) {
- x = fftCosR(j, nwh);
- y = fftSinR(j, nwh);
- // x = fftCos(delta * j);
- // y = fftSin(delta * j);
- w[j] = x;
- w[j + 1] = y;
- w[nw - j] = y;
- w[nw - j + 1] = x;
- }
- bitrv2(nw, ip + 2, w);
- }
- }
- }
- void makect(int nc, int *ip, fftType *c)
- {
- // int j, nch;
- long j, nch;
- // fftType delta;
-
- ip[1] = nc;
- if (nc > 1) {
- nch = nc >> 1;
- // delta = fftM_PI_4/nch; // atan(1.0) / nch;
- // c[0] = fftCos(delta * nch);
- c[0] = fftCosR(nch, nch);
- c[nch] = 0.5 * c[0];
- for (j = 1; j < nch; j++) {
- // c[j] = 0.5 * fftCos(delta * j);
- // c[nc - j] = 0.5 * fftSin(delta * j);
- c[j] = 0.5 * fftCosR(j, nch);
- c[nc - j] = 0.5 * fftSinR(j, nch);
- }
- }
- }
- #endif // USES_SIN_COS_TABLE
-
- void cftfsub(int n, fftType *a, fftType *w)
- {
- int j, j1, j2, j3, l;
- fftType x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
-
- l = 2;
- if (n > 8) {
- cft1st(n, a, w);
- l = 8;
- while ((l << 2) < n) {
- cftmdl(n, l, a, w);
- l <<= 2;
- }
- }
- if ((l << 2) == n) {
- for (j = 0; j < l; 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;
- }
- } else {
- for (j = 0; j < l; 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;
- }
- }
- }
-
-
- void cftbsub(int n, fftType *a, fftType *w)
- {
- int j, j1, j2, j3, l;
- fftType x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
-
- l = 2;
- if (n > 8) {
- cft1st(n, a, w);
- l = 8;
- while ((l << 2) < n) {
- cftmdl(n, l, a, w);
- l <<= 2;
- }
- }
- if ((l << 2) == n) {
- for (j = 0; j < l; 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;
- }
- } else {
- for (j = 0; j < l; 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[j + 1] - a[j1 + 1];
- a[j1] = x0r;
- a[j1 + 1] = x0i;
- }
- }
- }
-
-
- void cft1st(int n, fftType *a, fftType *w)
- {
- int j, k1, k2;
- fftType wk1r, wk1i, wk2r, wk2i, wk3r, wk3i;
- fftType x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
-
- x0r = a[0] + a[2];
- x0i = a[1] + a[3];
- x1r = a[0] - a[2];
- x1i = a[1] - a[3];
- x2r = a[4] + a[6];
- x2i = a[5] + a[7];
- x3r = a[4] - a[6];
- x3i = a[5] - a[7];
- a[0] = x0r + x2r;
- a[1] = x0i + x2i;
- a[4] = x0r - x2r;
- a[5] = x0i - x2i;
- a[2] = x1r - x3i;
- a[3] = x1i + x3r;
- a[6] = x1r + x3i;
- a[7] = x1i - x3r;
- wk1r = w[2];
- x0r = a[8] + a[10];
- x0i = a[9] + a[11];
- x1r = a[8] - a[10];
- x1i = a[9] - a[11];
- x2r = a[12] + a[14];
- x2i = a[13] + a[15];
- x3r = a[12] - a[14];
- x3i = a[13] - a[15];
- a[8] = x0r + x2r;
- a[9] = x0i + x2i;
- a[12] = x2i - x0i;
- a[13] = x0r - x2r;
- x0r = x1r - x3i;
- x0i = x1i + x3r;
- a[10] = wk1r * (x0r - x0i);
- a[11] = wk1r * (x0r + x0i);
- x0r = x3i + x1r;
- x0i = x3r - x1i;
- a[14] = wk1r * (x0i - x0r);
- a[15] = wk1r * (x0i + x0r);
- k1 = 0;
- for (j = 16; j < n; j += 16) {
- k1 += 2;
- k2 = 2 * k1;
- wk2r = w[k1];
- wk2i = w[k1 + 1];
- wk1r = w[k2];
- wk1i = w[k2 + 1];
- wk3r = wk1r - 2 * wk2i * wk1i;
- wk3i = 2 * wk2i * wk1r - wk1i;
- x0r = a[j] + a[j + 2];
- x0i = a[j + 1] + a[j + 3];
- x1r = a[j] - a[j + 2];
- x1i = a[j + 1] - a[j + 3];
- x2r = a[j + 4] + a[j + 6];
- x2i = a[j + 5] + a[j + 7];
- x3r = a[j + 4] - a[j + 6];
- x3i = a[j + 5] - a[j + 7];
- a[j] = x0r + x2r;
- a[j + 1] = x0i + x2i;
- x0r -= x2r;
- x0i -= x2i;
- a[j + 4] = wk2r * x0r - wk2i * x0i;
- a[j + 5] = wk2r * x0i + wk2i * x0r;
- x0r = x1r - x3i;
- x0i = x1i + x3r;
- a[j + 2] = wk1r * x0r - wk1i * x0i;
- a[j + 3] = wk1r * x0i + wk1i * x0r;
- x0r = x1r + x3i;
- x0i = x1i - x3r;
- a[j + 6] = wk3r * x0r - wk3i * x0i;
- a[j + 7] = wk3r * x0i + wk3i * x0r;
- wk1r = w[k2 + 2];
- wk1i = w[k2 + 3];
- wk3r = wk1r - 2 * wk2r * wk1i;
- wk3i = 2 * wk2r * wk1r - wk1i;
- x0r = a[j + 8] + a[j + 10];
- x0i = a[j + 9] + a[j + 11];
- x1r = a[j + 8] - a[j + 10];
- x1i = a[j + 9] - a[j + 11];
- x2r = a[j + 12] + a[j + 14];
- x2i = a[j + 13] + a[j + 15];
- x3r = a[j + 12] - a[j + 14];
- x3i = a[j + 13] - a[j + 15];
- a[j + 8] = x0r + x2r;
- a[j + 9] = x0i + x2i;
- x0r -= x2r;
- x0i -= x2i;
- a[j + 12] = -wk2i * x0r - wk2r * x0i;
- a[j + 13] = -wk2i * x0i + wk2r * x0r;
- x0r = x1r - x3i;
- x0i = x1i + x3r;
- a[j + 10] = wk1r * x0r - wk1i * x0i;
- a[j + 11] = wk1r * x0i + wk1i * x0r;
- x0r = x1r + x3i;
- x0i = x1i - x3r;
- a[j + 14] = wk3r * x0r - wk3i * x0i;
- a[j + 15] = wk3r * x0i + wk3i * x0r;
- }
- }
- void cftmdl(int n, int l, fftType *a, fftType *w)
- {
- int j, j1, j2, j3, k, k1, k2, m, m2;
- fftType wk1r, wk1i, wk2r, wk2i, wk3r, wk3i;
- fftType x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
-
- m = l << 2;
- for (j = 0; j < l; 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;
- }
- wk1r = w[2];
- for (j = m; j < l + m; 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 = 0;
- m2 = 2 * m;
- for (k = m2; k < n; k += m2) {
- k1 += 2;
- k2 = 2 * k1;
- wk2r = w[k1];
- wk2i = w[k1 + 1];
- wk1r = w[k2];
- wk1i = w[k2 + 1];
- wk3r = wk1r - 2 * wk2i * wk1i;
- wk3i = 2 * wk2i * wk1r - wk1i;
- for (j = k; j < l + k; 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;
- }
- wk1r = w[k2 + 2];
- wk1i = w[k2 + 3];
- wk3r = wk1r - 2 * wk2r * wk1i;
- wk3i = 2 * wk2r * wk1r - wk1i;
- for (j = k + m; j < l + (k + m); 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] = -wk2i * x0r - wk2r * x0i;
- a[j2 + 1] = -wk2i * x0i + wk2r * 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;
- }
- }
- }
- void rftfsub(int n, fftType *a, int nc, fftType *c)
- {
- int j, k, kk, ks, m;
- fftType wkr, wki, xr, xi, yr, yi;
-
- m = n >> 1;
- ks = 2 * nc / m;
- kk = 0;
- for (j = 2; j < m; j += 2) {
- k = n - j;
- kk += ks;
- wkr = 0.5 - c[nc - kk];
- wki = c[kk];
- xr = a[j] - a[k];
- xi = a[j + 1] + a[k + 1];
- yr = wkr * xr - wki * xi;
- yi = wkr * xi + wki * xr;
- a[j] -= yr;
- a[j + 1] -= yi;
- a[k] += yr;
- a[k + 1] -= yi;
- }
- }
-
-
- void rftbsub(int n, fftType *a, int nc, fftType *c)
- {
- int j, k, kk, ks, m;
- fftType wkr, wki, xr, xi, yr, yi;
-
- a[1] = -a[1];
- m = n >> 1;
- ks = 2 * nc / m;
- kk = 0;
- for (j = 2; j < m; j += 2) {
- k = n - j;
- kk += ks;
- wkr = 0.5 - c[nc - kk];
- wki = c[kk];
- xr = a[j] - a[k];
- xi = a[j + 1] + a[k + 1];
- yr = wkr * xr + wki * xi;
- yi = wkr * xi - wki * xr;
- a[j] -= yr;
- a[j + 1] = yi - a[j + 1];
- a[k] += yr;
- a[k + 1] = yi - a[k + 1];
- }
- a[m + 1] = -a[m + 1];
- }
rdft4g.cpp : last modifiled at 2017/07/26 10:59:45(20,130 bytes)
created at 2016/04/11 11:17:20
The creation time of this html file is 2017/10/07 10:54:16 (Sat Oct 07 10:54:16 2017).