Matrix: GHS_psdef/ford1

Description: Gould, Hu, & Scott: car surface mesh, from Pothen & Kumfert

GHS_psdef/ford1 graph
(undirected graph drawing)


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  • Matrix group: GHS_psdef
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  • download as a MATLAB mat-file, file size: 166 KB. Use UFget(1262) or UFget('GHS_psdef/ford1') in MATLAB.
  • download in Matrix Market format, file size: 154 KB.
  • download in Rutherford/Boeing format, file size: 145 KB.

    Matrix properties
    number of rows18,728
    number of columns18,728
    structural full rank?yes
    structural rank18,728
    # of blocks from dmperm1
    # strongly connected comp.1
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    Cholesky candidate?yes
    positive definite?no

    authorG. Kumfert, A. Pothen
    editorN. Gould, Y. Hu, J. Scott
    kindstructural problem
    2D/3D problem?yes

    Ordering statistics:result
    nnz(chol(P*(A+A'+s*I)*P')) with AMD303,615
    Cholesky flop count1.4e+07
    nnz(L+U), no partial pivoting, with AMD588,502
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD652,845
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD1,237,976

    SVD-based statistics:
    null space dimension534
    full numerical rank?no
    singular value gap9.9064e+09

    singular values (MAT file):click here
    SVD method used:s = svd (full (R)) ; where [~,R,E] = spqr (A) with droptol of zero

    GHS_psdef/ford1 svd

    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.