• SJSU Singular Matrix Database
  • 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/jgl011
  • Description: U JOHN G. LEWIS P4 COUNTEREXAMPLE WHICH REQUIRES FILL IN SPIKES
  • download as a MATLAB mat-file, file size: 763 bytes. Use SJget(135) or SJget('HB/jgl011') in MATLAB.
  • download in Matrix Market format, file size: 614 bytes.
  • download in Rutherford/Boeing format, file size: 571 bytes.

    HB/jgl011

    Routine svd from Matlab 7.6.0.324 (R2008a) used to calculate the singular values.

    HB/jgl011

    Matrix properties (click for a legend)  
    number of rows11
    number of columns11
    structural full rank?yes
    structural rank11
    numerical rank 5
    dimension of the numerical null space6
    numerical rank / min(size(A))0.45455
    Euclidean norm of A 7.6949
    calculated singular value # 50.90416
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    9.77e-015
    calculated singular value # 62.2642e-016
    gap in the singular values at the numerical rank:
    singular value # 5 / singular value # 6
    3.9933e+015
    calculated condition number3.2432e+066
    condestInf
    nonzeros76
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries0
    nonzero pattern symmetry 52%
    numeric value symmetry 52%
    typebinary
    structureunsymmetric
    Cholesky candidate?no
    positive definite?no

    authorJ. Lewis
    editorI. Duff, R. Grimes, J. Lewis
    date1983
    kindcounter-example problem
    2D/3D problem?no
    SJid135
    UFid186

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))60 60
    Cholesky flop count4.1e+002 4.1e+002
    nnz(L+U), no partial pivoting109 109
    nnz(V) for QR, upper bound nnz(L) for LU47 59
    nnz(R) for QR, upper bound nnz(U) for LU66 66

    Maintained by Leslie Foster, last updated 24-Apr-2009.

    Entries 5 through 14 in the table of matrix properties and the singular
    value plot were created using SJsingular code. The other plots
    and statistics are produced using utilities from the SuiteSparse package.
    Matrix color plot pictures by cspy, a MATLAB function in the CSparse package.