HB/ash292 graph

Matrix: HB/ash292

Description: SYMMETRIC PATTERN OF NORMAL MATRIX OF U.K. SURVEY. ASHKENAZI, 1974

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  • Matrix group: HB
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    HB/ash292

    Matrix properties
    number of rows292
    number of columns292
    nonzeros2,208
    structural full rank?yes
    structural rank292
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    typebinary
    structuresymmetric
    Cholesky candidate?yes
    positive definite?no

    authorV. Askenazi
    editorA. Curtis, I. Duff, J. Reid
    date1974
    kindleast squares problem
    2D/3D problem?no

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))2,496 2,766
    Cholesky flop count2.5e+04 3.2e+04
    nnz(L+U), no partial pivoting4,700 5,240
    nnz(V) for QR, upper bound nnz(L) for LU3,251 3,817
    nnz(R) for QR, upper bound nnz(U) for LU6,186 7,071

    Maintained by Tim Davis, last updated 30-Sep-2008.
    Matrix pictures by cspy, a MATLAB function in the CSparse package.
    Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.