83 lines
3.4 KiB
C
83 lines
3.4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
|
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
|
|
╞══════════════════════════════════════════════════════════════════════════════╡
|
|
│ Copyright 2020 Justine Alexandra Roberts Tunney │
|
|
│ │
|
|
│ Permission to use, copy, modify, and/or distribute this software for │
|
|
│ any purpose with or without fee is hereby granted, provided that the │
|
|
│ above copyright notice and this permission notice appear in all copies. │
|
|
│ │
|
|
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
|
|
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
|
|
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
|
|
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
|
|
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
|
|
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
|
|
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
|
|
│ PERFORMANCE OF THIS SOFTWARE. │
|
|
╚─────────────────────────────────────────────────────────────────────────────*/
|
|
#include "dsp/core/core.h"
|
|
#include "dsp/core/q.h"
|
|
#include "libc/dce.h"
|
|
#include "libc/macros.h"
|
|
#include "libc/math.h"
|
|
#include "libc/str/str.h"
|
|
|
|
/**
|
|
* Same as GetIntegerCoefficients() but with eight terms.
|
|
* @cost ~3ms
|
|
*/
|
|
long GetIntegerCoefficients8(long N[static 8], const double C[static 8], long M,
|
|
long L, long H) {
|
|
int i;
|
|
int j[8], J[8];
|
|
int O[8] = {0};
|
|
int S[3] = {0, -1, +1};
|
|
double R[8], K[8], D[8], Z, least, error;
|
|
least = 1;
|
|
Z = 1L << M;
|
|
for (i = 0; i < ARRAYLEN(J); ++i) {
|
|
least *= H - L;
|
|
if (fabs(C[i]) > DBL_MIN) {
|
|
J[i] = ARRAYLEN(S);
|
|
R[i] = C[i] * Z;
|
|
K[i] = rint(R[i]);
|
|
N[i] = K[i];
|
|
} else {
|
|
J[i] = 1;
|
|
R[i] = 0;
|
|
K[i] = 0;
|
|
N[i] = 0;
|
|
}
|
|
}
|
|
if (least > 1) {
|
|
for (j[0] = 0; j[0] < J[0]; ++j[0]) {
|
|
for (j[1] = 0; j[1] < J[1]; ++j[1]) {
|
|
for (j[2] = 0; j[2] < J[2]; ++j[2]) {
|
|
for (j[3] = 0; j[3] < J[3]; ++j[3]) {
|
|
for (j[4] = 0; j[4] < J[4]; ++j[4]) {
|
|
for (j[5] = 0; j[5] < J[5]; ++j[5]) {
|
|
for (j[6] = 0; j[6] < J[6]; ++j[6]) {
|
|
for (j[7] = 0; j[7] < J[7]; ++j[7]) {
|
|
for (i = 0; i < ARRAYLEN(J); ++i) {
|
|
D[i] = S[j[i]] + K[i] - R[i];
|
|
}
|
|
if ((error = DifferSumSq8(D, L, H) / Z) < least) {
|
|
least = error;
|
|
memcpy(O, j, sizeof(j));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
for (i = 0; i < 8; ++i) {
|
|
N[i] += S[O[i]];
|
|
}
|
|
}
|
|
return lround(least);
|
|
}
|