• UF Sparse Matrix Collection
  • Matrix group: GHS_indef
  • Click here for a description of the GHS_indef group.
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  • Matrix: GHS_indef/bloweybq
  • Description: MATRIX FOR WHICH EARLY VERSION OF MA57 FAILS
  • download as a MATLAB mat-file, file size: 66 KB. Use UFget(1425) or UFget('GHS_indef/bloweybq') in MATLAB.
  • download in Matrix Market format
  • download in Rutherford/Boeing format

    GHS_indef/bloweybq

    GHS_indef/bloweybq graph

    Matrix properties
    number of rows10,001
    number of columns10,001
    nonzeros49,999
    structural full rank?yes
    structural rank10,001
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries19,992
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    typereal
    structuresymmetric
    Cholesky candidate?yes
    positive definite?yes

    authorJ. Blowey
    editorN. Gould
    date1992
    kindmaterials problem
    2D/3D problem?yes

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))39,996 53,226
    Cholesky flop count1.6e+05 2.9e+05
    nnz(L+U), no partial pivoting69,991 96,451
    nnz(V) for QR, upper bound nnz(L) for LU40,003 50,856
    nnz(R) for QR, upper bound nnz(U) for LU79,974 90,820

    Note that all matrix statistics (except nonzero pattern symmetry) exclude the 19992 explicit zero entries.

    Maintained by Tim Davis, last updated 04-May-2008.
    Matrix pictures by cspy, a MATLAB function in the CSparse package.
    Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.