Matrix: GHS_indef/aug2d

Description: Gould, Hu, & Scott: expanded system-2D PDE (CUTEr)

GHS_indef/aug2d graph
(undirected graph drawing)


GHS_indef/aug2d dmperm of GHS_indef/aug2d

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  • Matrix group: GHS_indef
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  • download as a MATLAB mat-file, file size: 137 KB. Use UFget(1215) or UFget('GHS_indef/aug2d') in MATLAB.
  • download in Matrix Market format, file size: 102 KB.
  • download in Rutherford/Boeing format, file size: 93 KB.

    Matrix properties
    number of rows29,008
    number of columns29,008
    nonzeros76,832
    structural full rank?no
    structural rank19,208
    # of blocks from dmperm2
    # strongly connected comp.1
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    typeinteger
    structuresymmetric
    Cholesky candidate?no
    positive definite?no

    authorN. Gould
    editorN. Gould
    date1994
    kind2D/3D problem
    2D/3D problem?yes

    Ordering statistics:result
    nnz(chol(P*(A+A'+s*I)*P')) with AMD248,374
    Cholesky flop count1.1e+07
    nnz(L+U), no partial pivoting, with AMD467,740
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD3,305,290
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD602,205

    SVD-based statistics:
    norm(A)2.82807
    min(svd(A))6.8258e-40
    cond(A)4.14321e+39
    rank(A)19,208
    sprank(A)-rank(A)0
    null space dimension9,800
    full numerical rank?no
    singular value gap5.35182e+11

    singular values (MAT file):click here
    SVD method used:s = svd (full (A))
    status:ok

    GHS_indef/aug2d 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.