mirror of
https://github.com/intel/isa-l.git
synced 2024-12-12 17:33:50 +01:00
82a6ac65dc
Add a program calculating some of the exact conditions where gf_gen_rs_matrix works, add comments stating these bounds to gf_gen_rs_matrix, and fix erasure code test that violates the bounds. Change-Id: I1d0010b09fea97731bfd24f4f76e24609538b24f Signed-off-by: Roy Oursler <roy.j.oursler@intel.com>
116 lines
2.8 KiB
C
116 lines
2.8 KiB
C
#include <string.h>
|
|
#include <stdint.h>
|
|
#include <stdio.h>
|
|
#include "erasure_code.h"
|
|
|
|
#define MAX_CHECK 63 /* Size is limited by using uint64_t to represent subsets */
|
|
#define M_MAX 0x20
|
|
#define K_MAX 0x10
|
|
#define ROWS M_MAX
|
|
#define COLS K_MAX
|
|
|
|
static inline int min(int a, int b)
|
|
{
|
|
if (a <= b)
|
|
return a;
|
|
else
|
|
return b;
|
|
}
|
|
|
|
void gen_sub_matrix(unsigned char *out_matrix, int dim, unsigned char *in_matrix, int rows,
|
|
int cols, uint64_t row_indicator, uint64_t col_indicator)
|
|
{
|
|
int i, j, r, s;
|
|
|
|
for (i = 0, r = 0; i < rows; i++) {
|
|
if (!(row_indicator & ((uint64_t) 1 << i)))
|
|
continue;
|
|
|
|
for (j = 0, s = 0; j < cols; j++) {
|
|
if (!(col_indicator & ((uint64_t) 1 << j)))
|
|
continue;
|
|
out_matrix[dim * r + s] = in_matrix[cols * i + j];
|
|
s++;
|
|
}
|
|
r++;
|
|
}
|
|
}
|
|
|
|
/* Gosper's Hack */
|
|
uint64_t next_subset(uint64_t * subset, uint64_t element_count, uint64_t subsize)
|
|
{
|
|
uint64_t tmp1 = *subset & -*subset;
|
|
uint64_t tmp2 = *subset + tmp1;
|
|
*subset = (((*subset ^ tmp2) >> 2) / tmp1) | tmp2;
|
|
if (*subset & (((uint64_t) 1 << element_count))) {
|
|
/* Overflow on last subset */
|
|
*subset = ((uint64_t) 1 << subsize) - 1;
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int are_submatrices_singular(unsigned char *vmatrix, int rows, int cols)
|
|
{
|
|
unsigned char matrix[COLS * COLS];
|
|
unsigned char invert_matrix[COLS * COLS];
|
|
uint64_t row_indicator, col_indicator, subset_init, subsize;
|
|
|
|
/* Check all square subsize x subsize submatrices of the rows x cols
|
|
* vmatrix for singularity*/
|
|
for (subsize = 1; subsize <= min(rows, cols); subsize++) {
|
|
subset_init = (1 << subsize) - 1;
|
|
col_indicator = subset_init;
|
|
do {
|
|
row_indicator = subset_init;
|
|
do {
|
|
gen_sub_matrix(matrix, subsize, vmatrix, rows,
|
|
cols, row_indicator, col_indicator);
|
|
if (gf_invert_matrix(matrix, invert_matrix, subsize))
|
|
return 1;
|
|
|
|
} while (next_subset(&row_indicator, rows, subsize) == 0);
|
|
} while (next_subset(&col_indicator, cols, subsize) == 0);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
unsigned char vmatrix[(ROWS + COLS) * COLS];
|
|
int rows, cols;
|
|
|
|
if (K_MAX > MAX_CHECK) {
|
|
printf("K_MAX too large for this test\n");
|
|
return 0;
|
|
}
|
|
if (M_MAX > MAX_CHECK) {
|
|
printf("M_MAX too large for this test\n");
|
|
return 0;
|
|
}
|
|
if (M_MAX < K_MAX) {
|
|
printf("M_MAX must be smaller than K_MAX");
|
|
return 0;
|
|
}
|
|
|
|
printf("Checking gen_rs_matrix for k <= %d and m <= %d.\n", K_MAX, M_MAX);
|
|
printf("gen_rs_matrix creates erasure codes for:\n");
|
|
|
|
for (cols = 1; cols <= K_MAX; cols++) {
|
|
for (rows = 1; rows <= M_MAX - cols; rows++) {
|
|
gf_gen_rs_matrix(vmatrix, rows + cols, cols);
|
|
|
|
/* Verify the Vandermonde portion of vmatrix contains no
|
|
* singular submatrix */
|
|
if (are_submatrices_singular(&vmatrix[cols * cols], rows, cols))
|
|
break;
|
|
|
|
}
|
|
printf(" k = %2d, m <= %2d \n", cols, rows + cols - 1);
|
|
|
|
}
|
|
return 0;
|
|
}
|