Basic HTML version of Foils prepared 8 November 1995

Foil 35 Banded Matrix Computational Complexity

From CPS615 Module on Iterative PDE Solvers CPS615 Basic Simulation Track for Computational Science -- Fall Semester 95. by Geoffrey C. Fox


1 One can show that in a general sparse matrix, it is straightforward to preserver the "end" zeros
2 000...000X000...000XXX000...000X000...000 shows structure of a row of A in 2D Laplace example
3 The first and last zeros can be explicitly taken into account by setting range of for loops properly
4 The inside zeros "fill" i.e. become nonzero during process of Gaussian elimination
5 Thus if bandwidth B i.e.
6 000...000X000...000XXX000...000X000...000
7 Then computational complexity is not N3 as for a full (no zeros accounted) but NB2

in Table To:


© on Tue Oct 28 1997