void twopassfft_scratch(multifile * infile, multifile * scratch,
long long nn, int isign)
{
long long n1, n2, bb, fp, ii, jj, kk, kind, df;
int move_size;
unsigned char *move;
rawtype *data, *dp;
double tmp1, tmp2, wtemp, wpi, wpr, wi, wr, delta;
if (nn < 2)
return;
/* Treat the input data as a n1 (rows) x n2 (cols) */
/* matrix. Make sure that n2 >= n1. */
n1 = good_factor(nn);
if (n1 == 0) {
printf("\nLength of FFT in twopassfft_scratch() must be factorable\n\n");
exit(1);
}
n2 = nn / n1;
bb = find_blocksize(n1, n2);
if (bb == 0) {
printf("\nCan't factor the FFT length in twopassfft_scratch()\n");
printf(" into useful sizes.\n\n");
exit(1);
}
data = gen_rawvect(bb * n2);
move_size = (bb + n2) / 2;
move = (unsigned char *) malloc(move_size);
/* First do n2 transforms of length n1 by */
/* fetching size bb x n1 blocks in memory. */
for (ii = 0; ii < n2; ii += bb) {
/* Read a n1 (rows) x bb (cols) block of data */
dp = data;
fp = sizeof(rawtype) * ii;
df = sizeof(rawtype) * n2;
for (jj = 0; jj < n1; jj++) {
fseek_multifile(infile, fp, SEEK_SET);
fread_multifile(dp, sizeof(rawtype), bb, infile);
dp += bb; /* Data ptr */
fp += df; /* File ptr */
}
/* Transpose the n1 (rows) x bb (cols) block of data */
transpose_fcomplex(data, n1, bb, move, move_size);
/* Do bb transforms of length n1 */
for (jj = 0; jj < bb; jj++)
COMPLEXFFT(data + jj * n1, n1, isign);
/* Multiply the matrix A(ii,jj) by exp(isign 2 pi i jj ii / nn). */
/* Use recursion formulas from Numerical Recipes. */
for (jj = 0; jj < bb; jj++) {
delta = isign * TWOPI * (ii + jj) / nn;
wr = cos(delta);
wi = sin(delta);
wtemp = sin(0.5 * delta);
wpr = -2.0 * wtemp * wtemp;
wpi = wi;
kind = jj * n1 + 1;
for (kk = 1; kk < n1; kk++, kind++) {
tmp1 = data[kind].r;
tmp2 = data[kind].i;
data[kind].r = tmp1 * wr - tmp2 * wi;
data[kind].i = tmp2 * wr + tmp1 * wi;
wtemp = wr;
wr = wtemp * wpr - wi * wpi + wr;
wi = wi * wpr + wtemp * wpi + wi;
}
}
fwrite_multifile(data, sizeof(rawtype), bb * n1, scratch);
}
/* Now do n1 transforms of length n2 by fetching */
/* groups of size n2 (rows) x bb (cols) blocks. */
for (ii = 0; ii < n1; ii += bb) {
/* Read two n2 (rows) x bb (cols) blocks from the file */
dp = data;
fp = sizeof(rawtype) * ii;
df = sizeof(rawtype) * n1;
for (jj = 0; jj < n2; jj++) {
fseek_multifile(scratch, fp, SEEK_SET);
fread_multifile(dp, sizeof(rawtype), bb, scratch);
dp += bb; /* Data ptr */
fp += df; /* File ptr */
}
/* Transpose the n2 (rows) x bb (cols) block of data */
transpose_fcomplex(data, n2, bb, move, move_size);
/* Do bb transforms of length n2 */
for (jj = 0; jj < bb; jj++)
COMPLEXFFT(data + jj * n2, n2, isign);
/* Transpose the bb (rows) x n2 (cols) block of data */
transpose_fcomplex(data, bb, n2, move, move_size);
/* Scale the data if needed */
if (isign == 1) {
tmp1 = 1.0 / (double) nn;
for (jj = 0; jj < n2 * bb; jj++) {
data[jj].r *= tmp1;
data[jj].i *= tmp1;
}
}
/* Write n2 (rows) x bb (cols) blocks to the file */
dp = data;
fp = sizeof(rawtype) * ii;
df = sizeof(rawtype) * n1;
for (jj = 0; jj < n2; jj++) {
fseek_multifile(infile, fp, SEEK_SET);
fwrite_multifile(dp, sizeof(rawtype), bb, infile);
dp += bb; /* Data ptr */
fp += df; /* File ptr */
}
}
free(move);
vect_free(data);
}
int main(int argc, char *argv[])
{
int ii, numfiles, filelen, datalen;
multifile *mfile;
float *data, *scratch;
char **filenames;
srand(3);
if (argc < 4) {
printf("usage: test_multifiles numfiles filelen datalen\n");
exit(0);
}
numfiles = atoi(argv[1]);
filenames = (char **) malloc(sizeof(char *) * numfiles);
filelen = atoi(argv[2]);
for (ii = 0; ii < numfiles; ii++) {
filenames[ii] = calloc(10, 1);
sprintf(filenames[ii], "test%d.dat", ii);
}
/* Generate the data and scratch spaces */
datalen = atoi(argv[3]);
data = gen_fvect(datalen);
scratch = gen_fvect(datalen);
for (ii = 0; ii < datalen; ii++)
data[ii] = (float) 2.0 *(rand() / ((double) RAND_MAX)) - 1.0;
/* Write the data */
printf("\nWrite test...\n");
mfile = fopen_multifile(numfiles, filenames, "w", filelen);
print_multifile(mfile, 1);
fwrite_multifile(data, sizeof(float), datalen, mfile);
print_multifile(mfile, 0);
fclose_multifile(mfile);
/* Read the data */
printf("\nRead test...\n");
mfile = fopen_multifile(numfiles, filenames, "r", 0);
print_multifile(mfile, 1);
fread_multifile(scratch, sizeof(float), datalen, mfile);
print_multifile(mfile, 0);
fclose_multifile(mfile);
/* Compare data and scratch */
for (ii = 0; ii < datalen; ii++) {
if (scratch[ii] != data[ii])
printf("Data point %d doesn't match: %f, %f\n", ii, data[ii], scratch[ii]);
}
/* Seek to a random place in the file and check that data */
printf("\nSeek test...\n");
{
long long byteindex;
mfile = fopen_multifile(numfiles, filenames, "r", 0);
print_multifile(mfile, 1);
byteindex = mfile->filelens[0] + mfile->filelens[1]
- sizeof(float) * 10;
print_multifile(mfile, 0);
fseek_multifile(mfile, byteindex, SEEK_SET);
print_multifile(mfile, 0);
fread_multifile(scratch + byteindex / sizeof(float), sizeof(float), 30, mfile);
print_multifile(mfile, 0);
fclose_multifile(mfile);
}
/* Compare data and scratch */
for (ii = 0; ii < datalen; ii++) {
if (scratch[ii] != data[ii])
printf("Data point %d doesn't match: %f, %f\n", ii, data[ii], scratch[ii]);
}
/* Free stuff up */
vect_free(data);
vect_free(scratch);
for (ii = 0; ii < numfiles; ii++)
free(filenames[ii]);
free(filenames);
exit(0);
}