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Convergence improvement for coupled cluster calculations

N. Mosyagin·E. Eliav·U. Kaldor
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Abstract

Convergence problems in coupled-cluster iterations are discussed, and a new iteration scheme is proposed. Whereas the Jacobi method inverts only the diagonal part of the large matrix of equation coefficients, we invert a matrix which also includes a relatively small number of off-diagonal coefficients, selected according to the excitation amplitudes undergoing the largest change in the coupled cluster iteration. A test case shows that the new IPM (inversion of partial matrix) method gives much better convergence than the straightforward Jacobi-type scheme or such well-known convergence aids as the reduced linear equations or direct inversion in iterative subspace methods.

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N. Mosyagin, E. Eliav, U. Kaldor. 2000-09-17. Convergence improvement for coupled cluster calculations. https://doi.org/10.1088/0953-4075/34/3/311

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