## Abstract A new __O__(__N__ log __N__) FFT‐based method to expedite matrix–vector multiplies involving multilevel block‐Toeplitz (MBT) matrices is presented. The method is also a minimal memory method with __O__(__N__) memory requirements because only nonredundant entries of the MBT matrix are st
A submatrix algorithm for the matrix-vector multiplication of very large matrices
✍ Scribed by Roland Lindh; Per-Årke Malmquist
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 179 KB
- Volume
- 10
- Category
- Article
- ISSN
- 0192-8651
No coin nor oath required. For personal study only.
✦ Synopsis
In self-consistent field (SCF) calculations the construction of the Fock matrix is most time-consuming step. The Fock matrix construction may formally be seen as a matrix-vector multiplication, where the matrix is the supermatrix, Tikl, and the vector is the first-order density matrix, yi. This formalism should be optimal for vector machines. This is not, however, fully utilized in most programs running on computers with small core memory. The size of the 8 matrix, typically in the order of 106-108 elements, has forced programmers to implement other nonvectorizable methods. We will present a submatrixbased algorithm which will partition the supermatrix so that vectorizable methods can be employed. The method will also reduce the input/output.
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