Matrix: Muite/Chebyshev2
Description: Integration matrix, Chebyshev method, 4th order semilinear initial BVP
(bipartite graph drawing) | (graph drawing of A+A') |
Matrix properties | |
number of rows | 2,053 |
number of columns | 2,053 |
nonzeros | 18,447 |
structural full rank? | yes |
structural rank | 2,053 |
# of blocks from dmperm | 1 |
# strongly connected comp. | 1 |
explicit zero entries | 0 |
nonzero pattern symmetry | 50% |
numeric value symmetry | 0% |
type | real |
structure | unsymmetric |
Cholesky candidate? | no |
positive definite? | no |
author | B. Muite |
editor | T. Davis |
date | 2007 |
kind | structural problem |
2D/3D problem? | yes |
Additional fields | size and type |
b | full 2053-by-1 |
Notes:
Chebyshev integration matrix from Benson Muite, Oxford. Details of the matrices can be found in a preprint at http://www.maths.ox.ac.uk/~muite entitled "A comparison of Chebyshev methods for solving fourth-order semilinear initial boundary value problems," June 2007. These matrices are very ill-conditioned, partly because of the dense rows which are hard to scale when coupled with the rest of the matrix.
Ordering statistics: | result |
nnz(chol(P*(A+A'+s*I)*P')) with AMD | 14,347 |
Cholesky flop count | 1.0e+05 |
nnz(L+U), no partial pivoting, with AMD | 26,641 |
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD | 8,208 |
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD | 2,108,431 |
SVD-based statistics: | |
norm(A) | 20277.2 |
min(svd(A)) | 3.65964e-12 |
cond(A) | 5.54075e+15 |
rank(A) | 2,051 |
sprank(A)-rank(A) | 2 |
null space dimension | 2 |
full numerical rank? | no |
singular value gap | 2.65179e+06 |
singular values (MAT file): | click here |
SVD method used: | s = svd (full (A)) ; |
status: | ok |
For a description of the statistics displayed above, click here.
Maintained by Tim Davis, last updated 12-Mar-2014.
Matrix pictures by cspy, a MATLAB function in the CSparse package.
Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.