text recu works

Code/ldpc/src/construction/random.rs

@@ -12,7 +12,9 @@ pub fn generate_random_h(rows: usize, cols: usize, wc: usize, wr: usize) -> Matr
 
         for c in 0..cols {
             let mut ones_placed = 0;
-            let mut avail_rows: Vec<usize> = (0..rows).filter(|&r| row_w[r] < wr).collect();
+            let mut avail_rows: Vec<usize> = (0..rows)
+                .filter(|&r| row_w[r] < wr && !creates_cycle_4(rows, cols, &data, r, c))
+                .collect();
 
             if avail_rows.len() < wc {
                 // Les problèmes...
@@ -60,3 +62,16 @@ pub fn generate_random_h_for_k(k: usize, wc: usize, wr: usize) -> MatrixGF2 {
     }
     best_h
 }
+
+fn creates_cycle_4(rows: usize, cols: usize, data: &[u8], row: usize, col: usize) -> bool {
+    for r2 in 0..rows {
+        if r2 != row && data[r2 * cols + col] == 1 {
+            for c2 in 0..col {
+                if data[row * cols + c2] == 1 && data[r2 * cols + c2] == 1 {
+                    return true;
+                }
+            }
+        }
+    }
+    false
+}

Code/ldpc/src/decoder/bit_flip.rs

@@ -1,3 +1,5 @@
+use rand::RngExt;
+
 use crate::code::LdpcCode;
 
 pub struct BitFlipDecoder<'a> {
@@ -35,6 +37,7 @@ impl<'a> BitFlipDecoder<'a> {
                 }
             }
 
+            // println!("poid syndome: {s_w}");
             // Aucune erreurs
             if s_w == 0 {
                 return Some(curr_bits);
@@ -65,8 +68,21 @@ impl<'a> BitFlipDecoder<'a> {
                     curr_bits[i] ^= 1; // Bit flip
                 }
             }
+            // Seuil de 3
+            // if max_cpt >= 3 {
+            //     for i in 0..n {
+            //         if cpt[i] == max_cpt {
+            //             curr_bits[i] ^= 1;
+            //         }
+            //     }
+            // } else if max_cpt > 0 {
+            //     if let Some(idx) = cpt.iter().position(|&x| x == max_cpt) {
+            //         curr_bits[idx] ^= 1;
+            //     }
+            // } else {
+            //     break;
+            // }
         }
-
-        return Some(curr_bits);
+        None
     }
 }

Code/ldpc/src/encoder/dense.rs

@@ -7,6 +7,7 @@ pub struct DenseEncoder {
     pub k: usize,
     pub n: usize,
     pub col_swaps: Vec<(usize, usize)>,
+    pub rank: usize,
 }
 
 impl DenseEncoder {
@@ -33,6 +34,7 @@ impl DenseEncoder {
             k,
             n,
             col_swaps,
+            rank,
         }
     }
 
@@ -48,10 +50,25 @@ impl DenseEncoder {
             .collect();
 
         // Reverse les changement de colonnes
-        for &(c1, c2) in self.col_swaps.iter().rev() {
-            codeword.swap(c1, c2);
-        }
+        // for &(c1, c2) in self.col_swaps.iter().rev() {
+        //     codeword.swap(c1, c2);
+        // }
+        self.g_matrix
+            .apply_inverse_permutation(&mut codeword, &self.col_swaps);
 
         codeword
     }
+
+    pub fn extract_message(&self, decoded_codeword: &[u8]) -> Vec<u8> {
+        let mut working_copy = decoded_codeword.to_vec();
+
+        self.g_matrix
+            .apply_permutation(&mut working_copy, &self.col_swaps);
+
+        let mut message = Vec::with_capacity(self.k);
+        for i in 0..self.k {
+            message.push(working_copy[self.rank + i]);
+        }
+        message
+    }
 }

Code/ldpc/src/main.rs

@@ -7,25 +7,28 @@ mod encoder;
 mod matrix;
 mod simulation;
 mod tanner;
+mod utils;
 
 use analysis::{AnalysisConfig, Analyzer, DecoderAlgorithm};
 
 fn main() {
-    println!("Analyse des performences");
+    // println!("Analyse des performences");
 
-    let config = AnalysisConfig {
-        k_values: vec![50, 200, 400, 800, 1000],
-        wc_values: vec![3, 4, 5],
-        wr_values: vec![6, 8, 9, 12, 15, 16],
-        min_error_prob: 0.00,
-        max_error_prob: 0.12,
-        steps: 15,
-        frames_per_step: 1000,
-        max_iter: 50,
-        algorithm: DecoderAlgorithm::BitFlipping,
-    };
+    // let config = AnalysisConfig {
+    //     k_values: vec![50, 200, 400, 800, 1000],
+    //     wc_values: vec![3, 4, 5],
+    //     wr_values: vec![6, 8, 9, 12, 15, 16],
+    //     min_error_prob: 0.00,
+    //     max_error_prob: 0.12,
+    //     steps: 15,
+    //     frames_per_step: 1000,
+    //     max_iter: 50,
+    //     algorithm: DecoderAlgorithm::BitFlipping,
+    // };
+    //
+    // let res = Analyzer::run_batch(config);
+    // Analyzer::save_csv(&res, "ldpc_analysis_results.csv");
 
-    let res = Analyzer::run_batch(config);
-    Analyzer::save_csv(&res, "ldpc_analysis_results.csv");
-    // simulation::run_simulation(1000, 3, 6, 0.005);
+    let message = "Je suis un test";
+    simulation::run_simulation(message, 3, 6, 0.01);
 }

Code/ldpc/src/matrix.rs

@@ -130,4 +130,16 @@ impl MatrixGF2 {
         }
         (rank, col_swaps)
     }
+
+    pub fn apply_inverse_permutation(&self, data: &mut [u8], swaps: &[(usize, usize)]) {
+        for &(c1, c2) in swaps.iter().rev() {
+            data.swap(c1, c2);
+        }
+    }
+
+    pub fn apply_permutation(&self, data: &mut [u8], swaps: &[(usize, usize)]) {
+        for &(c1, c2) in swaps.iter() {
+            data.swap(c1, c2);
+        }
+    }
 }

Code/ldpc/src/simulation.rs

@@ -6,12 +6,15 @@ use crate::code::{self, LdpcCode};
 use crate::construction::random::{generate_random_h, generate_random_h_for_k};
 use crate::decoder::bit_flip::BitFlipDecoder;
 use crate::encoder::dense::DenseEncoder;
+use crate::utils;
 use rand::{Rng, RngExt};
 
-pub fn run_simulation(k: usize, wc: usize, wr: usize, error_prob: f64) {
+pub fn run_simulation(text: &str, wc: usize, wr: usize, error_prob: f64) {
+    let mut message_bits = utils::string_to_bits(text);
+    let k = message_bits.len();
     println!(
-        "\nSimulation LDPC : k = {} bits, wc = {}, wr = {}, p = {:.2}",
-        k, wc, wr, error_prob
+        "\nSimulation LDPC : k = {} bits, wc = {}, wr = {}, p = {:.2}, text : {}",
+        k, wc, wr, error_prob, text
     );
 
     println!("Construction");
@@ -36,7 +39,9 @@ pub fn run_simulation(k: usize, wc: usize, wr: usize, error_prob: f64) {
     println!("Encodage");
 
     let mut rng = rand::rng();
-    let message: Vec<u8> = (0..k).map(|_| rng.random_range(0..2)).collect();
+    // let message: Vec<u8> = (0..k).map(|_| rng.random_range(0..2)).collect();
+    let mut message = message_bits.clone();
+    message.resize(encoder.k, 0);
 
     let codeword = encoder.encode(&message);
 
@@ -64,21 +69,27 @@ pub fn run_simulation(k: usize, wc: usize, wr: usize, error_prob: f64) {
     }
 
     let decoder = BitFlipDecoder::new(&ldpc);
-    let max_iter = 50;
+    let max_iter = 100;
 
     match decoder.decode(&received, max_iter) {
         Some(decoded) => {
+            let decoded_message_bits = encoder.extract_message(&decoded);
+            let res_text = utils::bits_to_string(&decoded_message_bits);
             if decoded == codeword {
                 println!("  -> Réussite");
             } else {
                 println!("  -> Echec : le decoder a convergé vers un mauvais codeword");
             }
+            println!("  -> Texte recu : {}", res_text);
         }
         None => {
+            let rec_bits = encoder.extract_message(&received);
+            let failed_text = utils::bits_to_string(&rec_bits);
             println!(
                 "  -> Echec : impossible decorriger après {} itérations",
                 max_iter
             );
+            println!("  -> Texte recu : {}", failed_text);
         }
     }
 }

Code/ldpc/src/utils.rs

@@ -0,0 +1,26 @@
+pub fn string_to_bits(s: &str) -> Vec<u8> {
+    let mut bits = Vec::new();
+    for byte in s.as_bytes() {
+        for i in (0..8).rev() {
+            bits.push((byte >> i) & 1);
+        }
+    }
+    bits
+}
+
+pub fn bits_to_string(bits: &[u8]) -> String {
+    let mut bytes = Vec::new();
+    for chunk in bits.chunks(8) {
+        if chunk.len() < 8 {
+            break;
+        }
+        let mut byte = 0u8;
+        for (i, &bit) in chunk.iter().enumerate() {
+            if bit == 1 {
+                byte |= 1 << (7 - i);
+            }
+        }
+        bytes.push(byte);
+    }
+    String::from_utf8_lossy(&bytes).into_owned()
+}