Hardesty/Hardesty1
2D biharmonic operator w/Langrage constraints, for smoothing
Name 
Hardesty1 
Group 
Hardesty 
Matrix ID 
2831 
Num Rows

938,905 
Num Cols

938,905 
Nonzeros

12,143,314 
Pattern Entries

12,143,314 
Kind

Computer Graphics/Vision Problem 
Symmetric

Yes 
Date

2013 
Author

S. Hardesty 
Editor

T. Davis 
Structural Rank 
938,905 
Structural Rank Full 
true 
Num Dmperm Blocks

7,811 
Strongly Connect Components

1 
Num Explicit Zeros

0 
Pattern Symmetry

100% 
Numeric Symmetry

100% 
Cholesky Candidate

no 
Positive Definite

no 
Type

integer 
Download 
MATLAB
Rutherford Boeing
Matrix Market

Notes 
Surface fitting problem for visualization, Sean Hardesty
Visualization of 3D structures in the earth
The Hardesty3 matrix is an interpolation matrix stacked above a
weighted Laplacian, to to fit a surface z(x,y) to a set of points
in R^3 subject to a smoothness constraint enforced via regularization.
Hardesty2 is a smaller version of this problem.
For the big matrix (Hardesty/Hardesty3), sparse QR (via SuiteSparseQR,
or SPQR) finds an R factor and a set of Householder vectors (Q.H) with
about 150 million nonzeros. Sparse LU factorization (with UMFPACK
v5.7.1) sees very high fillin (about 2.5 billion nonzeros in L+U).
The Hardesty1 matrix is a simple discretization of a 2D biharmonic
operator with some Lagrange multiplier constraints used for smoothing.
