计算智能大题

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下面的伪代码实现了计算智能中某一算法的核心迭代过程,请根据上下文填写代码。 % 以旅行商问题(TSP)为背景的蚁群算法核心迭代过程 function [best_path, best_path_length] = ant_colony_optimization(distance_matrix, num_cities, num_ants, alpha, beta, rho, Q, max_iter) % 初始化信息素矩阵,所有路径上的信息素初始化为一个较小的正数 pheromone = ones(num_cities, num_cities) / (num_cities * num_cities); best_path = []; best_path_length = inf; for iteration = 1:max_iter all_paths = cell(1, num_ants); % 存储所有蚂蚁的路径 all_lengths = zeros(1, num_ants); % 存储所有蚂蚁的路径长度 for ant = 1:num_ants % 1. 初始化:随机选择一个起始城市,并将该城市加入禁忌列表 start_city = randi(num_cities); tabu_list = [start_city]; % 禁忌列表 path = [start_city]; % 当前路径 % 2. (1) ______:所有蚂蚁依次选择下一个城市,直到访问完所有城市 for step = 1:num_cities - 1 current_city = path(end); next_city = choose_next_city(current_city, tabu_list, pheromone, distance_matrix, alpha, beta); path = [path, next_city]; tabu_list = [tabu_list, next_city]; end % 计算当前蚂蚁的路径总长度 path_length = calculate_path_length(path, distance_matrix); all_paths{ant} = path; all_lengths(ant) = path_length; % 更新全局最优解 if path_length < best_path_length best_path_length = path_length; best_path = path; end end % 3. 更新信息素:先对所有路径上的信息素进行挥发,再根据蚂蚁行走的路径增加信息素 % (2) ______:所有路径上的信息素以速率 rho 挥发 pheromone = (1 - rho) * pheromone; for ant_index = 1:num_ants path = all_paths{ant_index}; % (3) 计算信息素增量 ______ contribution = Q / all_lengths(ant_index); for k = 1:num_cities - 1 city_i = path(k); city_j = path(k+1); pheromone(city_i, city_j) = pheromone(city_i, city_j) + contribution; end % 处理从最后一个城市返回起始城市的路径 pheromone(path(end), path(1)) = pheromone(path(end), path(1)) + contribution; end end % 选择下一个城市的概率规则函数 function next_city = choose_next_city(current_city, tabu_list, pheromone, distance_matrix, alpha, beta) num_cities = size(distance_matrix, 1); probabilities = zeros(1, num_cities); for next_city_idx = 1:num_cities if ~ismember(next_city_idx, tabu_list) % (4) 计算能见度 ______ eta = 1.0 / (distance_matrix(current_city, next_city_idx) + 1e-10); prob = (pheromone(current_city, next_city_idx) ^ alpha) * (eta ^ beta); probabilities(next_city_idx) = prob; else probabilities(next_city_idx) = 0; end end total_prob = sum(probabilities); if total_prob == 0 % 随机选择一个未访问的城市 available = setdiff(1:num_cities, tabu_list); next_city = available(randi(length(available))); return; end % 轮盘赌选择 rand_val = rand() * total_prob; cumulative_prob = 0; for next_city_idx = 1:num_cities if ~ismember(next_city_idx, tabu_list) cumulative_prob = cumulative_prob + probabilities(next_city_idx); if cumulative_prob >= rand_val next_city = next_city_idx; return; end end end % 保底选择 available = setdiff(1:num_cities, tabu_list); next_city = available(randi(length(available))); end function length = calculate_path_length(path, distance_matrix) length = 0; for i = 1:length(path)-1 length = length + distance_matrix(path(i), path(i+1)); end % 加上从最后一个城市返回起始城市的距离 length = length + distance_matrix(path(end), path(1)); end
下面的Matlab代码实现了人工蜂群算法中跟随蜂搜索的核心过程,请根据上下文填写代码。 % 人工蜂群算法 - 跟随蜂阶段(轮盘赌选择) % X: 当前种群矩阵(引领蜂),大小为 (NP/2) x D % F: 适应度值向量,大小为 NP/2 % NP: 总种群数量(代表食物源数量) % D: 问题维度 % trial: 计数器向量 % limit: 最大搜索限制次数 function [X, F, trial] = onlooker_bees_phase(X, F, trial, NP, D, limit, lb, ub) % 1. (1) ______:计算每个解被选择的概率 total_fitness = sum(F); probabilities = F / total_fitness; % 2. 每个跟随蜂根据概率选择引领蜂进行搜索 for i = 1:NP/2 % 轮盘赌选择一个引领蜂 r = rand(); cumulative_prob = 0; selected_index = 0; for j = 1:NP/2 cumulative_prob = cumulative_prob + probabilities(j); if r <= cumulative_prob selected_index = j; break; end end % 如果没有选中(理论上不会发生),随机选一个 if selected_index == 0 selected_index = randi(NP/2); end % 3. 随机选择一个与selected_index不同的其他引领蜂个体r1 r1 = selected_index; while r1 == selected_index r1 = randi(NP/2); end % 4. (2) ______:随机选择一个维度进行搜索 j = randi(D); % 5. 生成新解 V V = X(selected_index, :); V(j) = X(selected_index, j) + (-1 + 2 * rand) * (X(selected_index, j) - X(r1, j)); % 6. 边界处理 V(j) = max(V(j), lb(j)); V(j) = min(V(j), ub(j)); % 7. 计算新解适应度 fV = calculate_fitness(V); % 假设函数已定义 % 8. (3) ______:贪婪选择,决定是否替换 if fV > F(selected_index) X(selected_index, :) = V; F(selected_index) = fV; trial(selected_index) = 0; else trial(selected_index) = trial(selected_index) + 1; end end % 9. (4) ______:查找并处理超过limit的解 for i = 1:NP/2 if trial(i) > limit for j = 1:D X(i, j) = lb(j) + rand * (ub(j) - lb(j)); end F(i) = calculate_fitness(X(i, :)); trial(i) = 0; end end end % 适应度计算函数(示例:求解最小值问题) function fitness = calculate_fitness(x) % 目标函数 f(x) = sum(x.^2) f_value = sum(x.^2); % (5) ______:将最小化问题转化为适应度(最大化) fitness = 1 / (1 + f_value); end
下面的Matlab代码实现了粒子群算法(PSO)的核心迭代过程,请根据上下文填写代码。 % 粒子群算法(PSO)核心迭代过程 % 求解函数 f(x) = sum(x.^2) 的最小值,x为N维向量,取值范围[-100, 100] function [gbest, gbest_value] = pso_optimization(N, M, C1, C2, w, V_max, t_max) % N: 粒子维度(变量个数) % M: 种群规模 % C1, C2: 学习因子 % w: (1) ______ % V_max: 最大速度 % t_max: 最大迭代次数 % 初始化粒子位置(在[-100, 100]内随机) X = -100 + 200 * rand(M, N); % 初始化粒子速度(在[-V_max, V_max]内随机) V = -V_max + 2 * V_max * rand(M, N); % 初始化个体最优位置 P = X; % 计算初始适应度值 fitness = arrayfun(@(i) sum(X(i, :).^2), 1:M); P_fitness = fitness; % (2) ______:找到全局最优位置 [gbest_value, idx] = min(P_fitness); gbest = P(idx, :); % 迭代循环 for t = 1:t_max for i = 1:M % 生成随机数 r1 = rand(1, N); r2 = rand(1, N); % (3) ______:更新粒子速度 V(i, :) = w * V(i, :) + C1 * r1 .* (P(i, :) - X(i, :)) + C2 * r2 .* (gbest - X(i, :)); % 速度限制 V(i, :) = max(V(i, :), -V_max); V(i, :) = min(V(i, :), V_max); % 更新粒子位置 X(i, :) = X(i, :) + V(i, :); % 边界处理 X(i, :) = max(X(i, :), -100); X(i, :) = min(X(i, :), 100); % 计算新适应度 new_fitness = sum(X(i, :).^2); % (4) ______:更新个体最优 if new_fitness < P_fitness(i) P(i, :) = X(i, :); P_fitness(i) = new_fitness; end end % 更新全局最优 [current_best_val, idx] = min(P_fitness); if current_best_val < gbest_value gbest_value = current_best_val; gbest = P(idx, :); end end end % 主程序调用示例 % (5) 根据提供的代码,请判断这是哪种算法的核心迭代过程?
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