gmres_restart.m
c0f1bd65251dmaster

gmres_restart.m
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			function[x, beta, count]=gmres_restart(linearOperator, b, x0)

			% gmres_restart: Basic implementation of the Generalized minimal residual method
			% INPUT:
			% linearOperator: Function handle for a matrix-vector multiplication
			% b: Right-hand side
			% x0: Starting vector
			% OUTPUT:
			% x: Approximate solution
			% beta: Vector containing the errors
			% count: Number of iterations

			x=x0;
			beta_error=1;
			count=0;

			maxiter=40;
			maxiter_tot=200;
			reorth_tol=0.7;
			tol_error=1e-7;


			while beta_error>tol_error && count <= maxiter_tot
			[beta, x, H, k] = GMRES(linearOperator, b, x, maxiter, reorth_tol, tol_error);
			beta_error=beta(end);
			count=count+k;
			end

			if beta_error>tol_error && count > maxiter_tot
			disp(['The restarted GMRES method did not converge after ' num2str(count-k) ' iterations'])
			end
			end