"Player 0x71634ea9ea3878cfaddbe9be27669f86a90b2652 submitted 'walk_sa…

…t_adapt_tabu' for challenge satisfiability"

tig-algorithms/src/satisfiability/mod.rs

@@ -16,7 +16,7 @@
 
 // c001_a009
 
-// c001_a010
+pub mod walk_sat_adapt_tabu; // c001_a010
 
 // c001_a011
 

tig-algorithms/src/satisfiability/walk_sat_adapt_tabu/benchmarker_outbound.rs

@@ -0,0 +1,145 @@
+/*!
+Copyright 2024 Louis Silva
+
+Licensed under the TIG Benchmarker Outbound Game License v1.0 (the "License"); you 
+may not use this file except in compliance with the License. You may obtain a copy 
+of the License at
+
+https://github.com/tig-foundation/tig-monorepo/tree/main/docs/licenses
+
+Unless required by applicable law or agreed to in writing, software distributed
+under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+CONDITIONS OF ANY KIND, either express or implied. See the License for the specific
+language governing permissions and limitations under the License.
+ */
+
+// TIG's UI uses the pattern `tig_challenges::<challenge_name>` to automatically detect your algorithm's challenge
+use anyhow::Result;
+use rand::{Rng, SeedableRng};
+use rand::rngs::StdRng;
+use rand::seq::IteratorRandom;
+use std::collections::{HashSet, VecDeque};
+use tig_challenges::satisfiability::*;
+
+pub fn solve_challenge(challenge: &Challenge) -> Result<Option<Solution>> {
+    let mut rng = StdRng::seed_from_u64(challenge.seed as u64);
+    let num_variables = challenge.difficulty.num_variables;
+    let max_flips = 1000;
+    let initial_noise: f64 = 0.3;
+    let mut noise: f64 = initial_noise;
+    let mut variables: Vec<bool> = (0..num_variables).map(|_| rng.gen()).collect();
+    let mut best_solution: Option<Solution> = None;
+    let mut best_unsatisfied = usize::MAX;
+    let mut clause_weights: Vec<usize> = vec![1; challenge.clauses.len()];
+    let mut unsatisfied_clauses: HashSet<usize> = challenge.clauses.iter()
+        .enumerate()
+        .filter_map(|(i, clause)| if !clause_satisfied(clause, &variables) { Some(i) } else { None })
+        .collect();
+    let mut tabu_list: VecDeque<usize> = VecDeque::with_capacity(10);
+    let mut tabu_tenure = 10;
+
+    for flip in 0..max_flips {
+        let num_unsatisfied = unsatisfied_clauses.len();
+
+        // Update the best solution found so far
+        if num_unsatisfied < best_unsatisfied {
+            best_unsatisfied = num_unsatisfied;
+            best_solution = Some(Solution { variables: variables.clone() });
+
+            if num_unsatisfied == 0 {
+                return Ok(best_solution);
+            }
+        }
+
+        // Adaptive noise adjustment based on progress
+        if num_unsatisfied == best_unsatisfied {
+            noise = (noise + 0.005).min(1.0);
+        } else {
+            noise = (noise - 0.01).max(0.1);
+        }
+
+        // Dynamic adjustment of tabu tenure
+        tabu_tenure = (num_unsatisfied as f64 / best_unsatisfied as f64 * 10.0).max(5.0).min(20.0) as usize;
+
+        // Choose an unsatisfied clause
+        if let Some(&clause_idx) = unsatisfied_clauses.iter().choose(&mut rng) {
+            let clause = &challenge.clauses[clause_idx];
+
+            // Flip a variable with a heuristic
+            if rng.gen::<f64>() < noise {
+                // Random flip
+                if let Some(&literal) = clause.iter().choose(&mut rng) {
+                    let var_idx = literal.abs() as usize - 1;
+                    if !tabu_list.contains(&var_idx) {
+                        variables[var_idx] = !variables[var_idx];
+                        update_unsatisfied_clauses(&mut unsatisfied_clauses, &challenge.clauses, var_idx, &variables);
+                        tabu_list.push_back(var_idx);
+                        if tabu_list.len() > tabu_tenure {
+                            tabu_list.pop_front();
+                        }
+                    }
+                }
+            } else {
+                // Greedy flip
+                let mut best_var = None;
+                let mut best_reduction = usize::MAX;
+                for &literal in clause {
+                    let var_idx = literal.abs() as usize - 1;
+                    if tabu_list.contains(&var_idx) {
+                        continue;
+                    }
+                    variables[var_idx] = !variables[var_idx]; // Tentative flip
+                    let reduction = challenge.clauses.iter().enumerate()
+                        .filter(|(i, clause)| !clause_satisfied(clause, &variables) && clause_weights[*i] > 0)
+                        .count();
+                    variables[var_idx] = !variables[var_idx]; // Revert flip
+
+                    if reduction < best_reduction {
+                        best_reduction = reduction;
+                        best_var = Some(var_idx);
+                    }
+                }
+
+                if let Some(var_idx) = best_var {
+                    variables[var_idx] = !variables[var_idx];
+                    update_unsatisfied_clauses(&mut unsatisfied_clauses, &challenge.clauses, var_idx, &variables);
+                    tabu_list.push_back(var_idx);
+                    if tabu_list.len() > tabu_tenure {
+                        tabu_list.pop_front();
+                    }
+                }
+            }
+
+            // Adaptive weight update for unsatisfied clauses
+            for &clause_idx in &unsatisfied_clauses {
+                clause_weights[clause_idx] += 1 + (best_unsatisfied.saturating_sub(num_unsatisfied)) / best_unsatisfied;
+            }
+        }
+    }
+
+    Ok(best_solution)
+}
+
+fn clause_satisfied(clause: &[i32], variables: &[bool]) -> bool {
+    clause.iter().any(|&literal| {
+        let var_idx = literal.abs() as usize - 1;
+        (literal > 0 && variables[var_idx]) || (literal < 0 && !variables[var_idx])
+    })
+}
+
+fn update_unsatisfied_clauses(
+    unsatisfied_clauses: &mut HashSet<usize>,
+    clauses: &[Vec<i32>],
+    flipped_var: usize,
+    variables: &[bool]
+) {
+    for (i, clause) in clauses.iter().enumerate() {
+        if clause.iter().any(|&literal| literal.abs() as usize - 1 == flipped_var) {
+            if clause_satisfied(clause, variables) {
+                unsatisfied_clauses.remove(&i);
+            } else {
+                unsatisfied_clauses.insert(i);
+            }
+        }
+    }
+}

tig-algorithms/src/satisfiability/walk_sat_adapt_tabu/commercial.rs

@@ -0,0 +1,145 @@
+/*!
+Copyright 2024 Louis Silva
+
+Licensed under the TIG Commercial License v1.0 (the "License"); you 
+may not use this file except in compliance with the License. You may obtain a copy 
+of the License at
+
+https://github.com/tig-foundation/tig-monorepo/tree/main/docs/licenses
+
+Unless required by applicable law or agreed to in writing, software distributed
+under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+CONDITIONS OF ANY KIND, either express or implied. See the License for the specific
+language governing permissions and limitations under the License.
+ */
+
+// TIG's UI uses the pattern `tig_challenges::<challenge_name>` to automatically detect your algorithm's challenge
+use anyhow::Result;
+use rand::{Rng, SeedableRng};
+use rand::rngs::StdRng;
+use rand::seq::IteratorRandom;
+use std::collections::{HashSet, VecDeque};
+use tig_challenges::satisfiability::*;
+
+pub fn solve_challenge(challenge: &Challenge) -> Result<Option<Solution>> {
+    let mut rng = StdRng::seed_from_u64(challenge.seed as u64);
+    let num_variables = challenge.difficulty.num_variables;
+    let max_flips = 1000;
+    let initial_noise: f64 = 0.3;
+    let mut noise: f64 = initial_noise;
+    let mut variables: Vec<bool> = (0..num_variables).map(|_| rng.gen()).collect();
+    let mut best_solution: Option<Solution> = None;
+    let mut best_unsatisfied = usize::MAX;
+    let mut clause_weights: Vec<usize> = vec![1; challenge.clauses.len()];
+    let mut unsatisfied_clauses: HashSet<usize> = challenge.clauses.iter()
+        .enumerate()
+        .filter_map(|(i, clause)| if !clause_satisfied(clause, &variables) { Some(i) } else { None })
+        .collect();
+    let mut tabu_list: VecDeque<usize> = VecDeque::with_capacity(10);
+    let mut tabu_tenure = 10;
+
+    for flip in 0..max_flips {
+        let num_unsatisfied = unsatisfied_clauses.len();
+
+        // Update the best solution found so far
+        if num_unsatisfied < best_unsatisfied {
+            best_unsatisfied = num_unsatisfied;
+            best_solution = Some(Solution { variables: variables.clone() });
+
+            if num_unsatisfied == 0 {
+                return Ok(best_solution);
+            }
+        }
+
+        // Adaptive noise adjustment based on progress
+        if num_unsatisfied == best_unsatisfied {
+            noise = (noise + 0.005).min(1.0);
+        } else {
+            noise = (noise - 0.01).max(0.1);
+        }
+
+        // Dynamic adjustment of tabu tenure
+        tabu_tenure = (num_unsatisfied as f64 / best_unsatisfied as f64 * 10.0).max(5.0).min(20.0) as usize;
+
+        // Choose an unsatisfied clause
+        if let Some(&clause_idx) = unsatisfied_clauses.iter().choose(&mut rng) {
+            let clause = &challenge.clauses[clause_idx];
+
+            // Flip a variable with a heuristic
+            if rng.gen::<f64>() < noise {
+                // Random flip
+                if let Some(&literal) = clause.iter().choose(&mut rng) {
+                    let var_idx = literal.abs() as usize - 1;
+                    if !tabu_list.contains(&var_idx) {
+                        variables[var_idx] = !variables[var_idx];
+                        update_unsatisfied_clauses(&mut unsatisfied_clauses, &challenge.clauses, var_idx, &variables);
+                        tabu_list.push_back(var_idx);
+                        if tabu_list.len() > tabu_tenure {
+                            tabu_list.pop_front();
+                        }
+                    }
+                }
+            } else {
+                // Greedy flip
+                let mut best_var = None;
+                let mut best_reduction = usize::MAX;
+                for &literal in clause {
+                    let var_idx = literal.abs() as usize - 1;
+                    if tabu_list.contains(&var_idx) {
+                        continue;
+                    }
+                    variables[var_idx] = !variables[var_idx]; // Tentative flip
+                    let reduction = challenge.clauses.iter().enumerate()
+                        .filter(|(i, clause)| !clause_satisfied(clause, &variables) && clause_weights[*i] > 0)
+                        .count();
+                    variables[var_idx] = !variables[var_idx]; // Revert flip
+
+                    if reduction < best_reduction {
+                        best_reduction = reduction;
+                        best_var = Some(var_idx);
+                    }
+                }
+
+                if let Some(var_idx) = best_var {
+                    variables[var_idx] = !variables[var_idx];
+                    update_unsatisfied_clauses(&mut unsatisfied_clauses, &challenge.clauses, var_idx, &variables);
+                    tabu_list.push_back(var_idx);
+                    if tabu_list.len() > tabu_tenure {
+                        tabu_list.pop_front();
+                    }
+                }
+            }
+
+            // Adaptive weight update for unsatisfied clauses
+            for &clause_idx in &unsatisfied_clauses {
+                clause_weights[clause_idx] += 1 + (best_unsatisfied.saturating_sub(num_unsatisfied)) / best_unsatisfied;
+            }
+        }
+    }
+
+    Ok(best_solution)
+}
+
+fn clause_satisfied(clause: &[i32], variables: &[bool]) -> bool {
+    clause.iter().any(|&literal| {
+        let var_idx = literal.abs() as usize - 1;
+        (literal > 0 && variables[var_idx]) || (literal < 0 && !variables[var_idx])
+    })
+}
+
+fn update_unsatisfied_clauses(
+    unsatisfied_clauses: &mut HashSet<usize>,
+    clauses: &[Vec<i32>],
+    flipped_var: usize,
+    variables: &[bool]
+) {
+    for (i, clause) in clauses.iter().enumerate() {
+        if clause.iter().any(|&literal| literal.abs() as usize - 1 == flipped_var) {
+            if clause_satisfied(clause, variables) {
+                unsatisfied_clauses.remove(&i);
+            } else {
+                unsatisfied_clauses.insert(i);
+            }
+        }
+    }
+}