Matrix: ND/nd24k

Description: ND problem set, matrix nd24k

ND/nd24k graph
(undirected graph drawing)


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  • Matrix group: ND
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  • download as a MATLAB mat-file, file size: 207 MB. Use UFget(939) or UFget('ND/nd24k') in MATLAB.
  • download in Matrix Market format, file size: 99 MB.
  • download in Rutherford/Boeing format, file size: 77 MB.

    Matrix properties
    number of rows72,000
    number of columns72,000
    structural full rank?yes
    structural rank72,000
    # of blocks from dmperm1
    # strongly connected comp.1
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    Cholesky candidate?yes
    positive definite?yes

    authorauthor unknown
    editorT. Davis
    kind2D/3D problem
    2D/3D problem?yes

    Ordering statistics:result
    nnz(chol(P*(A+A'+s*I)*P')) with AMD511,595,052
    Cholesky flop count5.6e+12
    nnz(L+U), no partial pivoting, with AMD1,023,118,104
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD456,249,857
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD932,849,973

    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.