Matrix: GHS_indef/qpband

Description: QPBAND augmented system - 20000 rows

GHS_indef/qpband graph
(undirected graph drawing)

GHS_indef/qpband dmperm of GHS_indef/qpband
scc of GHS_indef/qpband

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  • Matrix group: GHS_indef
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  • download as a MATLAB mat-file, file size: 98 KB. Use UFget(1427) or UFget('GHS_indef/qpband') in MATLAB.
  • download in Matrix Market format, file size: 79 KB.
  • download in Rutherford/Boeing format, file size: 93 KB.

    Matrix properties
    number of rows20,000
    number of columns20,000
    structural full rank?yes
    structural rank20,000
    # of blocks from dmperm5,000
    # strongly connected comp.5,000
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    Cholesky candidate?no
    positive definite?no

    authorN. Gould
    editorN. Gould
    kindoptimization problem
    2D/3D problem?no

    Ordering statistics:result
    nnz(chol(P*(A+A'+s*I)*P')) with AMD35,000
    Cholesky flop count6.5e+04
    nnz(L+U), no partial pivoting, with AMD50,000
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD40,000
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD50,000

    SVD-based statistics:
    null space dimension0
    full numerical rank?yes

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

    GHS_indef/qpband 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.