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-rw-r--r--controller/fw/ldpc_decoder.c267
1 files changed, 0 insertions, 267 deletions
diff --git a/controller/fw/ldpc_decoder.c b/controller/fw/ldpc_decoder.c
deleted file mode 100644
index fe59d77..0000000
--- a/controller/fw/ldpc_decoder.c
+++ /dev/null
@@ -1,267 +0,0 @@
-
-#include <stdint.h>
-#include <unistd.h>
-#include <stdbool.h>
-#include <math.h>
-#include <stdio.h>
-
-
-void gausselimination(size_t n, size_t k, int8_t *A, int8_t *b);
-
-void inner_logbp(
- size_t m, size_t n,
- size_t bits_count, size_t nodes_count, const uint32_t bits_values[], const uint32_t nodes_values[],
- int8_t Lc[],
- float Lq[], float Lr[],
- unsigned int n_iter,
- float L_posteriori_out[]);
-
-//decode(384, 6, 8, ...)
-int decode(size_t n, size_t nodes_count, size_t bits_count, uint32_t bits[], int8_t y[], int8_t out[], unsigned int maxiter) {
- const size_t m = n * nodes_count / bits_count;
- float Lq[m*n];
- float Lr[m*n];
- float L_posteriori[n];
-
- /* Calculate column bit positions from row bit positions */
- int32_t bits_transposed[nodes_count * n];
- for (size_t i=0; i<nodes_count * n; i++)
- bits_transposed[i] = -1;
-
- for (size_t i=0; i<m; i++) {
- for (size_t j=0; j<bits_count; j++) {
- int32_t *base = bits_transposed + bits[i*bits_count + j] * nodes_count;
- for (; *base != -1; base++)
- ;
- *base = i;
- }
- }
-
- /*
- printf("Row positions: [");
- for (size_t i=0; i<m*bits_count; i++) {
- if (i)
- printf(", ");
- if (i%32 == 0)
- printf("\n ");
- printf("%4d", bits[i]);
- }
- printf("\n]\n");
-
- printf("Column positions: [");
- for (size_t i=0; i<n*nodes_count; i++) {
- if (i)
- printf(", ");
- if (i%32 == 0)
- printf("\n ");
- printf("%4d", bits_transposed[i]);
- }
- printf("\n]\n");
- */
-
- /* Run iterative optimization algorithm */
- for (unsigned int n_iter=0; n_iter<maxiter; n_iter++) {
- inner_logbp(m, n, bits_count, nodes_count, bits, (uint32_t*)bits_transposed, y, Lq, Lr, n_iter, L_posteriori);
-
- /*
- float *arrs[3] = {Lq, Lr, L_posteriori};
- const char *names[3] = {"Lq", "Lr", "L_posteriori"};
- size_t lens[3] = {m*n, m*n, n};
- const size_t head_tail = 10;
- for (int j=0; j<3; j++) {
- printf("%s=[", names[j]);
- bool ellipsis = false;
- const int w = 16;
- for (size_t i=0; i<lens[j]; i++) {
- if (lens[j] > 1000 && i/w > head_tail && i/w < m*n/w-head_tail) {
- if (!ellipsis) {
- ellipsis = true;
- printf("\n ...");
- }
- continue;
- }
- if (i)
- printf(", ");
- if (i%w == 0)
- printf("\n ");
- float outf = arrs[j][i];
- char *s = outf < 0 ? "\033[91m" : (outf > 0 ? "\033[92m" : "\033[94m");
- printf("%s% 012.6g\033[38;5;240m", s, outf);
- }
- printf("\n]\n");
- }
- */
-
- for (size_t i=0; i<n; i++)
- out[i] = L_posteriori[i] <= 0.0f;
-
- for (size_t i=0; i<m; i++) {
- bool sum = 0;
- for (size_t j=0; j<bits_count; j++)
- sum ^= out[bits[i*bits_count + j]];
- if (sum)
- continue;
- }
-
- fflush(stdout);
- return n_iter;
- }
-
- fflush(stdout);
- return -1;
-}
-
-/* Perform inner ext LogBP solver */
-void inner_logbp(
- size_t m, size_t n,
- size_t bits_count, size_t nodes_count, uint32_t const bits_values[], const uint32_t nodes_values[],
- int8_t Lc[],
- float Lq[], float Lr[],
- unsigned int n_iter,
- float L_posteriori_out[]) {
-
- /*
- printf("Input data: [");
- for (size_t i=0; i<n; i++) {
- if (i)
- printf(", ");
- if (i%32 == 0)
- printf("\n ");
- printf("%4d", Lc[i]);
- }
- printf("\n]\n");
- */
-
- /* step 1 : Horizontal */
- unsigned int bits_counter = 0;
- for (size_t i=0; i<m; i++) {
- //printf("=== i=%zu\n", i);
- for (size_t p=bits_counter; p<bits_counter+bits_count; p++) {
- size_t j = bits_values[p];
- //printf("\033[38;5;240mj=%04zd ", j);
-
- float x = 1;
- if (n_iter == 0) {
- for (size_t q=bits_counter; q<bits_counter+bits_count; q++) {
- if (bits_values[q] != j) {
- //int lcv = Lc[bits_values[q]];
- //char *s = lcv < 0 ? "\033[91m" : (lcv > 0 ? "\033[92m" : "\033[94m");
- //printf("nij=%04u Lc=%s%3d\033[38;5;240m ", bits_values[q], s, lcv);
- x *= tanhf(0.5f * Lc[bits_values[q]]);
- }
- }
-
- } else {
- for (size_t q=bits_counter; q<bits_counter+bits_count; q++) {
- if (bits_values[q] != j)
- x *= tanhf(0.5f * Lq[i*n + bits_values[q]]);
- }
- }
-
- //printf("\n==== i=%03zd p=%01zd x=%08f\n", i, p-bits_counter, x);
-
- float num = 1 + x;
- float denom = 1 - x;
- if (num == 0)
- Lr[i*n + j] = -1.0f;
- else if (denom == 0)
- Lr[i*n + j] = 1.0f;
- else
- Lr[i*n + j] = logf(num/denom);
- }
-
- bits_counter += bits_count;
- }
-
- /* step 2 : Vertical */
- unsigned int nodes_counter = 0;
- for (size_t j=0; j<n; j++) {
- for (size_t p=bits_counter; p<nodes_counter+nodes_count; p++) {
- size_t i = nodes_values[p];
-
- Lq[i*n + j] = Lc[j];
-
- for (size_t q=bits_counter; q<nodes_counter+nodes_count; q++) {
- if (nodes_values[q] != i)
- Lq[i*n + j] += Lr[nodes_values[q]*n + j];
- }
- }
-
- nodes_counter += nodes_count;
- }
-
- /* LLR a posteriori */
- nodes_counter = 0;
- for (size_t j=0; j<n; j++) {
- float sum = 0;
- for (size_t k=bits_counter; k<nodes_counter+nodes_count; k++)
- sum += Lr[nodes_values[k]*n + j];
- nodes_counter += nodes_count;
-
- L_posteriori_out[j] = Lc[j] + sum;
- }
-}
-
-/* Compute the original (k) bit message from a (n) bit codeword x.
- *
- * tG: (n, k)-matrix
- * x: (n)-vector
- * out: (k)-vector
- */
-void get_message(size_t n, size_t k, int8_t *tG, int8_t *x, int8_t *out) {
-
- gausselimination(n, k, tG, x);
-
- out[k - 1] = x[k - 1];
- for (ssize_t i=k-2; i>=0; i--) {
- out[i] = x[i];
-
- uint8_t sum = 0;
- for (size_t j=i+1; j<k; j++)
- sum ^= tG[i*k + j] * out[j];
-
- out[i] = !!(out[i] - sum);
- }
-}
-
-/* Solve linear system in Z/2Z via Gauss Gauss elimination.
- *
- * A: (n, k)-matrix
- * b: (n)-vector
- */
-void gausselimination(size_t n, size_t k, int8_t *A, int8_t *b) {
- ssize_t d = k<n ? k : n;
- for (ssize_t j=0; j<d; j++) {
-
- ssize_t pivot = -1;
- for (size_t i=j; i<n; i++) {
- if (A[i*k + j]) {
- pivot = i;
- break;
- }
- }
- if (pivot == -1)
- continue;
-
- if (pivot != j) {
- for (size_t i=0; i<k; i++) {
- int8_t tmp = A[j*k + i];
- A[j*k + i] = A[pivot*k + i];
- A[pivot*k + i] = tmp;
- }
-
- int8_t tmp = b[j];
- b[j] = b[pivot];
- b[pivot] = tmp;
- }
-
- for (size_t i=j+1; i<n; i++) {
- if (A[i*k + j]) {
- for (size_t p=0; p<k; p++)
- A[i*k + p] = !!(A[i*k + p] - A[j*k + p]);
- b[i] = !!(b[i] - b[j]);
- }
- }
- }
-}
-
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