• UF Sparse Matrix Collection
  • Matrix group: HB
  • Click here for a description of the HB group.
  • Click here for a list of all matrices
  • Click here for a list of all matrix groups


  • Matrix: HB/jgl009
  • Description: U JOHN G. LEWIS P4 COUNTEREXAMPLE WHICH REQUIRES FILL IN SPIKES
  • download as a MATLAB mat-file, file size: 521 bytes. Use UFget(185) or UFget('HB/jgl009') in MATLAB.
  • download in Matrix Market format
  • download in Rutherford/Boeing format

    HB/jgl009

    HB/jgl009 graph

    Matrix properties
    number of rows9
    number of columns9
    nonzeros50
    structural full rank?yes
    structural rank9
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries0
    nonzero pattern symmetry 48%
    numeric value symmetry 48%
    typebinary
    structureunsymmetric
    Cholesky candidate?no
    positive definite?no

    authorJ. Lewis
    editorI. Duff, R. Grimes, J. Lewis
    date1983
    kindcounter-example problem
    2D/3D problem?no

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))42 42
    Cholesky flop count2.4e+02 2.4e+02
    nnz(L+U), no partial pivoting75 75
    nnz(V) for QR, upper bound nnz(L) for LU44 44
    nnz(R) for QR, upper bound nnz(U) for LU45 45

    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.