UHSDR/UHSDR-active-devel/mchf-eclipse/drivers/freedv/mbest.c

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2022-11-08 16:13:55 +01:00
/*---------------------------------------------------------------------------*\
FILE........: mbest.c
AUTHOR......: David Rowe
DATE CREATED: Jan 2017
Multistage vector quantiser search algorithm that keeps multiple
candidates from each stage.
\*---------------------------------------------------------------------------*/
/*
Copyright David Rowe 2017
All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License version 2.1, as
published by the Free Software Foundation. This program is
distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "mbest.h"
struct MBEST *mbest_create(int entries) {
int i,j;
struct MBEST *mbest;
assert(entries > 0);
mbest = (struct MBEST *)malloc(sizeof(struct MBEST));
assert(mbest != NULL);
mbest->entries = entries;
mbest->list = (struct MBEST_LIST *)malloc(entries*sizeof(struct MBEST_LIST));
assert(mbest->list != NULL);
for(i=0; i<mbest->entries; i++) {
for(j=0; j<MBEST_STAGES; j++)
mbest->list[i].index[j] = 0;
mbest->list[i].error = 1E32;
}
return mbest;
}
void mbest_destroy(struct MBEST *mbest) {
assert(mbest != NULL);
free(mbest->list);
free(mbest);
}
/*---------------------------------------------------------------------------*\
mbest_insert
Insert the results of a vector to codebook entry comparison. The
list is ordered in order of error, so those entries with the
smallest error will be first on the list.
\*---------------------------------------------------------------------------*/
void mbest_insert(struct MBEST *mbest, int index[], float error) {
int i, j, found;
struct MBEST_LIST *list = mbest->list;
int entries = mbest->entries;
found = 0;
for(i=0; i<entries && !found; i++)
if (error < list[i].error) {
found = 1;
for(j=entries-1; j>i; j--)
list[j] = list[j-1];
for(j=0; j<MBEST_STAGES; j++)
list[i].index[j] = index[j];
list[i].error = error;
}
}
#ifdef MBEST_PRINT_OUT
static void mbest_print(char title[], struct MBEST *mbest) {
int i,j;
fprintf(stderr, "%s\n", title);
for(i=0; i<mbest->entries; i++) {
for(j=0; j<MBEST_STAGES; j++)
fprintf(stderr, " %4d ", mbest->list[i].index[j]);
fprintf(stderr, " %f\n", mbest->list[i].error);
}
}
#endif
/*---------------------------------------------------------------------------*\
mbest_search
Searches vec[] to a codebbook of vectors, and maintains a list of the mbest
closest matches.
\*---------------------------------------------------------------------------*/
void mbest_search(
const float *cb, /* VQ codebook to search */
float vec[], /* target vector */
float w[], /* weighting vector */
int k, /* dimension of vector */
int m, /* number on entries in codebook */
struct MBEST *mbest, /* list of closest matches */
int index[] /* indexes that lead us here */
)
{
float e;
int i,j;
float diff;
for(j=0; j<m; j++) {
e = 0.0;
for(i=0; i<k; i++) {
diff = cb[j*k+i]-vec[i];
e += diff*w[i]*diff*w[i];
}
index[0] = j;
mbest_insert(mbest, index, e);
}
}
/*---------------------------------------------------------------------------*\
mbest_search450
Searches vec[] to a codebbook of vectors, and maintains a list of the mbest
closest matches. Only searches the first NewAmp2_K Vectors
\*---------------------------------------------------------------------------*/
void mbest_search450(const float *cb, float vec[], float w[], int k,int shorterK, int m, struct MBEST *mbest, int index[])
{
float e;
int i,j;
float diff;
for(j=0; j<m; j++) {
e = 0.0;
for(i=0; i<k; i++) {
//Only search first NEWAMP2_K Vectors
if(i<shorterK){
diff = cb[j*k+i]-vec[i];
e += diff*w[i] * diff*w[i];
}
}
index[0] = j;
mbest_insert(mbest, index, e);
}
}