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avutil/tx_template: add some butterfly prime FFT codelets

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Paul B Mahol 2024-09-24 23:00:44 +02:00
parent 6ef3eea3c8
commit 62da31ba80
1 changed files with 220 additions and 0 deletions
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220
libavutil/tx_template.c
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@ -1358,6 +1358,217 @@ static void TX_NAME(ff_tx_fft_bluestein)(AVTXContext *s, void *_dst, void *_src,
}
}
static av_always_inline void cpx_add(TXComplex *out,
const TXComplex *in1,
const TXComplex *in2)
{
out->re = in1->re + in2->re;
out->im = in1->im + in2->im;
}
static av_always_inline void cpx_sub(TXComplex *out,
const TXComplex *in1,
const TXComplex *in2)
{
out->re = in1->re - in2->re;
out->im = in1->im - in2->im;
}
static av_always_inline void cpx_mul_s(TXComplex *out,
const TXComplex *in,
const TXSample s)
{
out->re = MULT(in->re, s);
out->im = MULT(in->im, s);
}
static av_always_inline void cpx_out(TXComplex *head,
TXComplex *tail,
const TXComplex *A,
const TXComplex *B)
{
head->re = A->re - B->im;
head->im = A->im + B->re;
tail->re = A->re + B->im;
tail->im = A->im - B->re;
}
static av_always_inline void cpx_mla(TXComplex *out,
const TXComplex *in1,
const TXComplex *in2,
const TXSample s)
{
out->re = in1->re + MULT(in2->re, s);
out->im = in1->im + MULT(in2->im, s);
}
static av_always_inline void cpx_neg(TXComplex *out,
const TXComplex *in)
{
out->re = -in->re;
out->im = -in->im;
}
static av_always_inline void cpx_zero(TXComplex *out)
{
out->re = 0;
out->im = 0;
}
static av_always_inline void like_terms(TXComplex *add,
TXComplex *sub,
const TXComplex *in,
const int r)
{
const int m = (r-1)/2;
if (r&1) {
add[0] = in[0];
cpx_neg(&sub[0], &in[0]);
} else {
cpx_add(&add[0], &in[0], &in[r/2]);
cpx_sub(&sub[0], &in[0], &in[r/2]);
}
for (int h = 1, t = r-1; h <= m; h++, t--) {
cpx_add(&add[h], &in[h], &in[t]);
cpx_sub(&sub[h], &in[h], &in[t]);
}
}
static av_always_inline void out_special(TXComplex *out,
const TXComplex *add,
const TXComplex *sub,
const int r)
{
const int m = r/2;
cpx_zero(&out[0]);
cpx_zero(&out[m]);
for (int i = 0; i <= m; i++)
cpx_add(&out[0], &out[0], &add[i]);
if (r&1)
return;
for (int i = 0; i < m; i += 2) {
cpx_add(&out[m], &out[m], &add[i+0]);
cpx_sub(&out[m], &out[m], &add[i+1]);
}
}
static av_always_inline void out_pair(TXComplex *out,
const TXComplex *add,
const TXComplex *sub,
const TXComplex *Wr,
const int k,
const int r)
{
TXComplex P, Q;
cpx_mla(&P, &add[0], &add[1], Wr[k].re);
cpx_mul_s(&Q, &sub[1], Wr[k].im);
for (int i = 2; i <= r/2; i++) {
cpx_mla(&P, &P, &add[i], Wr[i*k].re);
cpx_mla(&Q, &Q, &sub[i], Wr[i*k].im);
}
cpx_out(&out[k], &out[r-k], &P, &Q);
}
static av_always_inline void butterfly_kernel(TXComplex *out,
const TXComplex *in,
const TXComplex *Wr,
const int r, const int stage,
const int stride)
{
TXComplex tmp_out[r], tmp_in[r];
TXComplex add[r], sub[r];
memcpy(tmp_in, in, sizeof(*in) * r);
like_terms(add, sub, tmp_in, r);
out_special(tmp_out, add, sub, r);
if (1) {
for (int i = 1; i <= r/2; i++)
out_pair(tmp_out, add, sub, Wr, i, r);
} else {
}
for (int i = 0; i < r; i++)
out[i*stride] = tmp_out[i];
}
static int init_twiddles(AVTXContext *s, const int len)
{
const double phase = s->inv ? 2.0*M_PI/len : -2.0*M_PI/len;
if (!(s->exp = av_mallocz((len/2+1)*(len/2+1)*sizeof(*s->exp))))
return AVERROR(ENOMEM);
for (int i = 0; i <= len/2; i++) {
for (int j = 0; j <= len/2; j++) {
const double factor = phase*i*j;
s->exp[i*j] = (TXComplex){
RESCALE(cos(factor)),
RESCALE(sin(factor)),
};
}
}
return 0;
}
static av_cold int TX_NAME(ff_tx_fft_auto_init)(AVTXContext *s,
const FFTXCodelet *cd,
uint64_t flags,
FFTXCodeletOptions *opts,
int len, int inv,
const void *scale)
{
return init_twiddles(s, len);
}
#define DECL_BUTTERFLY_CODELET(n) \
static void TX_NAME(ff_tx_fft##n##_butterfly)(AVTXContext *s,\
void *_dst, void *_src, \
ptrdiff_t stride) \
{ \
TXComplex *in = _src; \
TXComplex *out = _dst; \
TXComplex *W = s->exp; \
\
stride /= sizeof(*out); \
\
butterfly_kernel(out, in, W, n, 0, stride); \
} \
\
static const FFTXCodelet TX_NAME(ff_tx_fft##n##_butterfly_def) = { \
.name = TX_NAME_STR("fft" #n "_butterfly"), \
.function = TX_NAME(ff_tx_fft##n##_butterfly), \
.type = TX_TYPE(FFT), \
.flags = FF_TX_OUT_OF_PLACE | AV_TX_INPLACE | \
AV_TX_UNALIGNED, \
.factors[0] = n, \
.nb_factors = 1, \
.min_len = n, \
.max_len = n, \
.init = TX_NAME(ff_tx_fft_auto_init), \
.cpu_flags = FF_TX_CPU_FLAGS_ALL, \
.prio = FF_TX_PRIO_MIN/5, \
};
DECL_BUTTERFLY_CODELET(11)
DECL_BUTTERFLY_CODELET(13)
DECL_BUTTERFLY_CODELET(17)
DECL_BUTTERFLY_CODELET(19)
DECL_BUTTERFLY_CODELET(23)
DECL_BUTTERFLY_CODELET(29)
DECL_BUTTERFLY_CODELET(31)
static const FFTXCodelet TX_NAME(ff_tx_fft_naive_small_def) = {
.name = TX_NAME_STR("fft_naive_small"),
.function = TX_NAME(ff_tx_fft_naive_small),
@ -2668,6 +2879,15 @@ const FFTXCodelet * const TX_NAME(ff_tx_codelet_list)[] = {
&TX_NAME(ff_tx_fft7_fwd_def),
&TX_NAME(ff_tx_fft9_fwd_def),
/* Butterfly prime transforms */
&TX_NAME(ff_tx_fft11_butterfly_def),
&TX_NAME(ff_tx_fft13_butterfly_def),
&TX_NAME(ff_tx_fft17_butterfly_def),
&TX_NAME(ff_tx_fft19_butterfly_def),
&TX_NAME(ff_tx_fft23_butterfly_def),
&TX_NAME(ff_tx_fft29_butterfly_def),
&TX_NAME(ff_tx_fft31_butterfly_def),
/* Standalone transforms */
&TX_NAME(ff_tx_fft_def),
&TX_NAME(ff_tx_fft_inplace_def),