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//////////////////////////////////////////////////////
// example of use of the simulated annealing method //
//////////////////////////////////////////////////////
function demo_sa_2()
my_handle = scf(100001);
clf(my_handle,"reset");
demo_viewCode("SAIsing2ddemo.sce");
my_handle.info_message = _("Please wait ...");
lines(0);
old_funcprot = funcprot();
funcprot(0);
// Loading the test problem
path = get_absolute_file_path("SAIsing2ddemo.sce");
getd(path + "/Ising");
// Loading the neighborhood function for the ising problem
getd(path + "/.");
Proba_start = 0.8;
It_intern = 1000;
It_extern = 30;
It_Pre = 100;
Log = %T;
alpha = 0.9;
Ising_Dim = 10;
Ising_Proba = 0.3;
J = 1.1;
H = 0.7;
Magnet = "%T";
Connect = "%T";
// For the minimization case, everything must be at -1 or 1 in the optimal solution
deff("y=f(x)","y = ising2d(x,"+string(J)+","+string(H)+","+Magnet+","+Connect+")");
// For the maximization case, we must have a checker board solution (+1 -1 +1 -1 ....)
//deff("y=f(x)","y = - ising2d(x,"+string(J)+","+string(H)+","+Magnet+","+Connect+")");
x0 = init_ising2d(Ising_Dim, Ising_Proba);
/////////////////////////
// Simulated Annealing //
/////////////////////////
printf("\nSA: geometrical decrease temperature law\n");
sa_params = init_param();
sa_params = add_param(sa_params,"dimension",10);
sa_params = add_param(sa_params,"proba",0.05);
sa_params = add_param(sa_params,"neigh_func", neigh_func_ising2d); // Required because this operator is specific to the ising2d problem
sa_params = add_param(sa_params,"accept_func", accept_func_default); // Optional
sa_params = add_param(sa_params,"temp_law", temp_law_default); // Optional
sa_params = add_param(sa_params,"alpha",alpha); // For the temperature decreasing law
T0 = compute_initial_temp(x0, f, Proba_start, It_Pre, sa_params);
printf("Initial temperature T0 = %f\n", T0);
[x_opt, f_opt, sa_mean_list, sa_var_list, temp_list] = optim_sa(x0, f, It_extern, It_intern, T0, Log, sa_params);
printf("optimal solution:\n"); disp(x_opt);
printf("value of the objective function = %f\n", f_opt);
if is_handle_valid(my_handle) then
plot_ising2d(x_opt);
my_handle.info_message = "";
end
funcprot(old_funcprot);
endfunction
demo_sa_2();
clear demo_sa_2;
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