• hguio
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  • matlab
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  • 2022-05-28 14:59
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NSGA-2
NSGA-II.rar
  • NSGA-II
  • fun.m
    48B
  • example_N.m
    416B
  • NSGAII.m
    6.7KB
内容介绍
function Rfit = NSGAII(params,MultiObj) Np = params.Np; maxgen = params.maxgen; pc = params.pc; pm = params.pm; ms = params.ms; fun = fun(x); nVar = MultiObj.nVar; var_min = MultiObj.var_min(:); var_max = MultiObj.var_max(:); gen = 1; P = repmat((var_max - var_min)', Np, 1) .* rand(Np, nVar) + repmat(var_min', Np, 1); Pfit = fun(P); Prank = FastNonDominatedSorting_Vectorized(Pfit); [P, ~] = selectParentByRank(P, Prank); Q = applyCrossoverAndMutation(P, pc, pm, ms, var_max, var_min); h_fig = figure(1); scatter(Pfit(:, 1), Pfit(:, 2), 20, 'filled', 'markerFaceAlpha', 0.3, 'MarkerFaceColor', [128, 193, 219] ./ 255); hold on h_rep = plot(Pfit(:,1), Pfit(:,2), 'ok'); hold on grid on xlabel('f1') ylabel('f2') drawnow axis square; display(['Generation #' num2str(gen) ' - First front size: ' num2str(sum(Prank==1))]); stopCondition = false; while ~stopCondition R = [P; Q]; Rfit = fun(R); Rrank = FastNonDominatedSorting_Vectorized(Rfit); figure(h_fig) delete(h_rep) scatter(Rfit(1 : Np, 1), Rfit(1 : Np, 2), 20, 'filled', 'markerFaceAlpha', 0.3, 'MarkerFaceColor', [128, 193 219] ./ 255); hold on h_rep = plot(Rfit(1 : Np, 1), Rfit(1 : Np, 2),'ok'); hold on; grid on xlabel('f1') ylabel('f2') drawnow; axis square; display(['Generation #' num2str(gen) ' - First front size: ' num2str(sum(Rrank==1))]); [Rrank,idx] = sort(Rrank, 'ascend'); Rfit = Rfit(idx, :); R = R(idx, :); [Rcrowd, Rrank, ~, R] = crowdingDistances(Rrank, Rfit, R); P = selectParentByRankAndDistance(Rcrowd, Rrank, R); Q = applyCrossoverAndMutation(P, pc, pm, ms, var_max, var_min); gen = gen + 1; if(gen > maxgen) stopCondition = true; end end end function newParent = selectParentByRankAndDistance(Rcrowd, Rrank, R) N = length(Rcrowd) / 2; Npf = length(unique(Rrank)); newParent = zeros(N, size(R, 2)); pf = 1; numberOfSolutions = 0; while pf <= Npf if numberOfSolutions + sum(Rrank == pf) <= N newParent(numberOfSolutions + 1 : numberOfSolutions + sum(Rrank == pf), :) = R(Rrank == pf, :); numberOfSolutions = numberOfSolutions + sum(Rrank == pf); else rest = N - numberOfSolutions; lastPF = R(Rrank == pf,:); lastPFdist = Rcrowd(Rrank == pf); [~,idx] = sort(lastPFdist, 'descend'); lastPF = lastPF(idx, :); newParent(numberOfSolutions + 1 : numberOfSolutions+rest, :) = lastPF(1 : rest, :); numberOfSolutions = numberOfSolutions + rest; end pf = pf + 1; end end function [sortCrowd, sortRank, sortFit, sortPop] = crowdingDistances(rank, fitness, pop) sortPop = []; sortFit = []; sortRank = []; sortCrowd = []; Npf = length(unique(rank)); for pf = 1 : 1 : Npf index = find(rank == pf); temp_fit = fitness(index, :); temp_rank = rank(index, :); temp_pop = pop(index, :); [temp_fit, sort_idx] = sortrows(temp_fit, 1); temp_rank = temp_rank(sort_idx); sortFit = [sortFit; temp_fit]; sortRank = [sortRank; temp_rank]; sortPop = [sortPop; temp_pop(sort_idx, :)]; temp_crowd = zeros(size(temp_rank)); for m = 1 : 1 : size(fitness, 2) temp_max = max(temp_fit(:, m)); temp_min = min(temp_fit(:, m)); for l = 2 : 1 : length(temp_crowd) - 1 temp_crowd(l) = temp_crowd(l) + (abs(temp_fit(l - 1, m) - temp_fit(l + 1, m))) ./ (temp_max - temp_min); end end temp_crowd(1) = Inf; temp_crowd(length(temp_crowd)) = Inf; sortCrowd = [sortCrowd; temp_crowd]; end end function Q = applyCrossoverAndMutation(parent, pc, pm, ms, var_max, var_min) N = size(parent, 1); nVar = size(parent, 2); Q = parent; cross_idx = rand(N, 1) < pc; cross_idx = find(cross_idx); for c = 1 : 1 : length(cross_idx) selected = randi(N, 1, 1); while selected == c selected = randi(N, 1, 1); end cut = randi(nVar, 1, 1); Q(c, :) = [parent(c, 1 : cut), parent(selected, cut + 1 : nVar)]; end mutatedPop = Q + ms .* repmat((var_max - var_min)', N, 1) .* randn(N, nVar); minVal = repmat(var_min', N, 1); maxVal = repmat(var_max', N, 1); mutatedPop(mutatedPop < minVal) = minVal(mutatedPop < minVal); mutatedPop(mutatedPop > maxVal) = maxVal(mutatedPop > maxVal); mut_idx = rand(N, nVar) < pm; Q(mut_idx) = mutatedPop(mut_idx); end function [P1, P1rank] = selectParentByRank(P, Prank) N = length(Prank); left_idx = randi(N, N, 1); right_idx = randi(N, N, 1); while sum(left_idx == right_idx) > 0 right_idx(left_idx == right_idx) = randi(N, sum(left_idx == right_idx), 1); end winners = zeros(N, 1); winners(Prank(left_idx) <= Prank(right_idx)) = left_idx(Prank(left_idx) <= Prank(right_idx)); winners(Prank(right_idx) < Prank(left_idx)) = right_idx(Prank(right_idx) < Prank(left_idx)); P1 = P(winners, :); P1rank = Prank(winners, :); end function RANK = FastNonDominatedSorting_Vectorized(fitness) Np = size(fitness, 1); RANK = zeros(Np, 1); current_vector = (1 : 1 : Np)'; current_pf = 1; all_perm = [repmat((1 : 1 : Np)', Np', 1), reshape(repmat((1: 1: Np), Np, 1), Np ^ 2, 1)]; all_perm(all_perm(:, 1) == all_perm(:, 2), :) = []; while ~isempty(current_vector) if length(current_vector) == 1 RANK(current_vector) = current_pf; break; end d = dominates(fitness(all_perm(:, 1), :), fitness(all_perm(:, 2), :)); dominated_particles = unique(all_perm(d == 1, 2)); if sum(~ismember(current_vector,dominated_particles)) == 0 break; end non_dom_idx = ~ismember(current_vector, dominated_particles); RANK(current_vector(non_dom_idx)) = current_pf; all_perm(ismember(all_perm(:, 1), current_vector(non_dom_idx)), :) = []; all_perm(ismember(all_perm(:, 2), current_vector(non_dom_idx)), :) = []; current_vector(non_dom_idx) = []; current_pf = current_pf + 1; end end function d = dominates(x,y) d = (all(x <= y, 2) & any(x < y, 2)); end
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