Computing the lowest eigenvalues of the Fermion matrix by subspace iterations
نویسنده
چکیده
provides the smallest eigenvalue, together with the corresponding eigenvector. The minimum of a functional can be found iteratively by the method of conjugate gradients (CG)[1], its application to the special case of the Ritz functional has been worked out by Geradin[2] and Fried[3]. If a small number of lowest eigenvalues is required instead, q(x) may be minimised repeatedly, restricting x to the space orthogonal to the previous eigenvectors. An efficient implementation of this idea is described in [4].
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