Local coordinate systems are chosen for each quadruple of atoms relative to a four-center integral, in order to avoid linear combinations of orbitals when symmetry operations perform on an orbital. This choice can utilize the complete molecular symmetry to attain the optimal number of symmetry-uniqu
On reduction schemes and the symmetry of a matrix
β Scribed by Ren, Gexue ;Cheng, Jiangang ;Jinwu, Xiang ;Lu, Qiuhai
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 88 KB
- Volume
- 15
- Category
- Article
- ISSN
- 1069-8299
No coin nor oath required. For personal study only.
β¦ Synopsis
In this paper, Lanczos and Arnoldi reduction methods as the special cases of the generalized Hessenberg method are brieΒ―y reviewed. Attention is paid to the eect of symmetry of matrices on the behaviour of the reduction schemes, such as serious numerical breakdown. Based on the summation decomposition of matrices, two structures of the upper Hessenberg form of a general unsymmetric matrix and their relationship are revealed, in terms of which, Arnoldi reduction schemes for unsymmetric matrices can be reformulated in two respective forms. The relationship between the reformulated reduction scheme and the current Lanczos schemes for skew and symmetric matrices are also discussed.
π SIMILAR VOLUMES
The KohnαSham KS procedure for variational minimization of the HohenbergαKohn density functional utilizes a one-particle reduced density matrix of assumed diagonal form, hence depends implicitly on a set of auxiliary states. Originally, the auxiliary state was assumed to be a single determinant with