121 lines
4.4 KiB
C
121 lines
4.4 KiB
C
#include "bf_decoding.h"
|
|
#include "dfr_test.h"
|
|
#include "gf2x_arith_mod_xPplusOne.h"
|
|
#include "qc_ldpc_parameters.h"
|
|
|
|
#include <string.h>
|
|
|
|
/* Tests if the current code attains the desired DFR. If that is the case,
|
|
* computes the threshold for the second iteration of the decoder and stores
|
|
* it in the globally accessible vector */
|
|
|
|
extern unsigned int thresholds[2];
|
|
|
|
int PQCLEAN_LEDAKEMLT52_CLEAN_DFR_test(POSITION_T LSparse[N0][DV * M]) {
|
|
|
|
POSITION_T LSparse_loc[N0][DV * M];
|
|
|
|
/* Gamma matrix: an N0 x N0 block circulant matrix with block size p
|
|
* gamma[a][b][c] stores the intersection of the first column of the a-th
|
|
* block of L with the c-th column of the b-th block of L */
|
|
/* Gamma computation can be accelerated employing symmetry and QC properties */
|
|
unsigned int gamma[N0][N0][P] = {{{0}}};
|
|
unsigned int rotated_column[DV * M];
|
|
|
|
unsigned int firstidx, secondidx, intersectionval;
|
|
|
|
unsigned int gammaHist[N0][DV * M + 1] = {{0}};
|
|
|
|
unsigned int maxMut[N0], maxMutMinusOne[N0];
|
|
unsigned int allBlockMaxSumst, allBlockMaxSumstMinusOne;
|
|
|
|
unsigned int toAdd, histIdx;
|
|
|
|
/*transpose blocks of L, we need its columns */
|
|
for (int i = 0; i < N0; i++) {
|
|
for (int j = 0; j < DV * M; j++) {
|
|
if (LSparse[i][j] != 0) {
|
|
LSparse_loc[i][j] = (P - LSparse[i][j]);
|
|
}
|
|
}
|
|
quicksort_sparse(LSparse_loc[i]);
|
|
}
|
|
|
|
for (int i = 0; i < N0; i++ ) {
|
|
for (int j = 0; j < N0; j++ ) {
|
|
for (int k = 0; k < P; k++) {
|
|
/* compute the rotated sparse column needed */
|
|
for (int idxToRotate = 0; idxToRotate < (DV * M); idxToRotate++) {
|
|
rotated_column[idxToRotate] = (LSparse_loc[j][idxToRotate] + k) % P;
|
|
}
|
|
quicksort_sparse(rotated_column);
|
|
/* compute the intersection amount */
|
|
firstidx = 0, secondidx = 0;
|
|
intersectionval = 0;
|
|
while ( (firstidx < DV * M) && (secondidx < DV * M) ) {
|
|
if ( LSparse_loc[i][firstidx] == rotated_column[secondidx] ) {
|
|
intersectionval++;
|
|
firstidx++;
|
|
secondidx++;
|
|
} else if ( LSparse_loc[i][firstidx] > rotated_column[secondidx] ) {
|
|
secondidx++;
|
|
} else { /*if ( LSparse_loc[i][firstidx] < rotated_column[secondidx] ) */
|
|
firstidx++;
|
|
}
|
|
}
|
|
gamma[i][j][k] = intersectionval;
|
|
|
|
}
|
|
}
|
|
}
|
|
for (int i = 0; i < N0; i++ ) {
|
|
for (int j = 0; j < N0; j++ ) {
|
|
gamma[i][j][0] = 0;
|
|
}
|
|
}
|
|
/* build histogram of values in gamma */
|
|
for (int i = 0; i < N0; i++ ) {
|
|
for (int j = 0; j < N0; j++ ) {
|
|
for (int k = 0; k < P; k++) {
|
|
gammaHist[i][gamma[i][j][k]]++;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
for (int gammaBlockRowIdx = 0; gammaBlockRowIdx < N0; gammaBlockRowIdx++) {
|
|
toAdd = T_BAR - 1;
|
|
maxMutMinusOne[gammaBlockRowIdx] = 0;
|
|
histIdx = DV * M;
|
|
while ( (histIdx > 0) && (toAdd > 0)) {
|
|
if (gammaHist[gammaBlockRowIdx][histIdx] > toAdd ) {
|
|
maxMutMinusOne[gammaBlockRowIdx] += histIdx * toAdd;
|
|
toAdd = 0;
|
|
} else {
|
|
maxMutMinusOne[gammaBlockRowIdx] += histIdx * gammaHist[gammaBlockRowIdx][histIdx];
|
|
toAdd -= gammaHist[gammaBlockRowIdx][histIdx];
|
|
histIdx--;
|
|
}
|
|
}
|
|
maxMut[gammaBlockRowIdx] = histIdx + maxMutMinusOne[gammaBlockRowIdx];
|
|
}
|
|
|
|
|
|
/*seek max values across all gamma blocks */
|
|
allBlockMaxSumst = maxMut[0];
|
|
allBlockMaxSumstMinusOne = maxMutMinusOne[0];
|
|
for (int gammaBlockRowIdx = 0; gammaBlockRowIdx < N0 ; gammaBlockRowIdx++) {
|
|
allBlockMaxSumst = allBlockMaxSumst < maxMut[gammaBlockRowIdx] ?
|
|
maxMut[gammaBlockRowIdx] :
|
|
allBlockMaxSumst;
|
|
allBlockMaxSumstMinusOne = allBlockMaxSumstMinusOne < maxMutMinusOne[gammaBlockRowIdx] ?
|
|
maxMutMinusOne[gammaBlockRowIdx] :
|
|
allBlockMaxSumstMinusOne;
|
|
}
|
|
if (DV * M > (allBlockMaxSumstMinusOne + allBlockMaxSumst)) {
|
|
thresholds[1] = allBlockMaxSumst + 1;
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|