double tf_shift(dofft_closure *k,
int realp, const bench_tensor *sz,
int n, int vecn, double sign,
C *inA, C *inB, C *outA, C *outB, C *tmp,
int rounds, double tol, int which_shift)
{
int nb, na, dim, N = n * vecn;
int i, j;
double e = 0.0;
/* test 3: check the time-shift property */
/* the paper performs more tests, but this code should be fine too */
nb = 1;
na = n;
/* check shifts across all SZ dimensions */
for (dim = 0; dim < sz->rnk; ++dim) {
int ncur = sz->dims[dim].n;
na /= ncur;
for (j = 0; j < rounds; ++j) {
arand(inA, N);
if (which_shift == TIME_SHIFT) {
for (i = 0; i < vecn; ++i) {
if (realp) mkreal(inA + i * n, n);
arol(inB + i * n, inA + i * n, ncur, nb, na);
}
k->apply(k, inA, outA);
k->apply(k, inB, outB);
for (i = 0; i < vecn; ++i)
aphase_shift(tmp + i * n, outB + i * n, ncur,
nb, na, sign);
e = dmax(e, acmp(tmp, outA, N, "time shift", tol));
} else {
for (i = 0; i < vecn; ++i) {
if (realp)
mkhermitian(inA + i * n, sz->rnk, sz->dims, 1);
aphase_shift(inB + i * n, inA + i * n, ncur,
nb, na, -sign);
}
k->apply(k, inA, outA);
k->apply(k, inB, outB);
for (i = 0; i < vecn; ++i)
arol(tmp + i * n, outB + i * n, ncur, nb, na);
e = dmax(e, acmp(tmp, outA, N, "freq shift", tol));
}
}
nb *= ncur;
}
return e;
}
static double verify_shift(fftd_func *dft,
int N,
COMPLEX *inA,
COMPLEX *inB,
COMPLEX *outA,
COMPLEX *outB,
COMPLEX *tmp,
int rounds)
{
const double twopin = 2 * M_PI / (double) N;
int i, j;
double e, maxerr = 0.0;
/* test 3: check the time-shift property */
/* the paper performs more tests, but this code should be fine too */
for (i = 0; i < rounds; ++i) {
fill_random(inA, N);
arol(inB, inA, N, 1);
dft((double *)outA, (double *)inA);
dft((double *)outB, (double *)inB);
for (j = 0; j < N; ++j) {
double s = SIGN * sin(j * twopin);
double c = cos(j * twopin);
int index = j;
RE(tmp[index]) = RE(outB[index]) * c - IM(outB[index]) * s;
IM(tmp[index]) = RE(outB[index]) * s + IM(outB[index]) * c;
}
e = acmp(tmp, outA, N);
if(e > maxerr) maxerr = e;
}
return maxerr;
}
