eig_string.m
33bba04159d6master

eig_string.m
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			L = 1.0
			N = 500
			dx = L / (N+1)

			A = diag(ones(N-1,1) * (-1), -1) + diag(ones(N,1) * 2, 0) + diag(ones(N-1,1) * (-1), 1);
			A = A / (dx^2);

			%[psi, lambda] = eig_ipower(A, 0);

			%disp("Smallest eigenvalue")
			%lambda

			x = (0:N-1) * dx;

			[eigval, eigvect] = eig_first(A, 5);

			for i = 1:5
			fprintf('%d-th eigenvalue: %g \n', i, eigval{i});
			end

			figure
			xlabel("x")
			ylabel("psi")
			plot(x, eigvect{1}, x, eigvect{2}, x, eigvect{3}, x, eigvect{4}, x, eigvect{5})
			legend('n = 1', 'n = 2', 'n = 3', 'n = 4', 'n = 5')

			% write out data
			eigs = fopen('output/eigs.out', 'w');
			for k = 1:N
			fprintf(eigs, '%g %g %g %g %g %g\n', x(k), eigvect{1}(k), eigvect{2}(k), eigvect{3}(k), eigvect{4}(k), eigvect{5}(k));
			end
			fclose(eigs);