83 lines
2.2 KiB
Matlab
83 lines
2.2 KiB
Matlab
function [] = iterations_over_lambda(method)
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% Plot iteration needed for different lambda values.
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%
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%
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% method: the minimum calculation method
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% * bisections
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% * golden_section
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% * fibonacci
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% * bisection_der
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% Load the functions and interval
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GivenEnv;
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fig_dir = 'figures';
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if ~exist(fig_dir, 'dir')
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mkdir(fig_dir);
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end
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% Setup
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% ========================
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%
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% We need to test against the same lambda values for all the methods in
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% order to compare them. And since epsilon (which is related to lambda)
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% was given for bisection method, we base our calculations to that.
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%
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%
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% epsilon: e = 0.001
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% lambda: l > 2e =>
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% lambda_min: 0.0021
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% lambda_max: 0.1
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% N: 50 points (50 lambda values)
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N = 50;
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epsilon = 0.001;
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lambda_min = 0.0021;
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lambda_max = 0.1;
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lambda = linspace(lambda_min, lambda_max, N);
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k = zeros(1, N); % preallocate k
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%
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% Call the minimum calculation method for each lambda value for each
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% function and keep the number of iterations needed.
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% Then plot and save the # of iterations k(lambda) for each function.
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%
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% note: In order to use the same method call for all methods, we force a
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% common interface for minimum method functions. Thus some arguments
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% will not be needed for some methods (epsilon is not needed for
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% bisection _der for example).
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%
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figure('Name', "iterations_over_lambda_" + char(method), 'NumberTitle', 'off');
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set(gcf, 'Position', [100, 100, 1280, 600]); % Set the figure size to HD
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disp(" ");
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for i = 1:length(funs)
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for j = N:-1:1
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[a, b, k(j)] = method(funs(i), a_0, b_0, epsilon, lambda(j));
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end
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fprintf('%20s(%34s ): [a, b]= [%f, %f], iterations(min, max)= (%d, %d)\n', ...
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char(method), char(funs(i)), a(end), b(end), k(N), k(1) );
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subplot(1, length(funs), i)
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plot(lambda, k, '-b', 'LineWidth', 1.0)
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title(titles(i), 'Interpreter', 'latex')
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xlabel('lambda')
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ylabel('Iterations')
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end
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%
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% Print and save the figures
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%
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%fig_epsc = fullfile(fig_dir, "iter_over_lambda_" + char(method) + ".epsc");
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fig_png = fullfile(fig_dir, "iter_over_lambda_" + char(method) + ".png");
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%print(gcf, fig_epsc, '-depsc', '-r300');
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print(gcf, fig_png, '-dpng', '-r300');
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