• SJSU Singular Matrix Database
  • Matrix group: HB
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  • Matrix: HB/curtis54
  • Description: UNSYMMETRIC PATTERN OF CURTIS, 1971
  • download as a MATLAB mat-file, file size: 1 KB. Use SJget(89) or SJget('HB/curtis54') in MATLAB.
  • download in Matrix Market format, file size: 1 KB.
  • download in Rutherford/Boeing format, file size: 882 bytes.

    HB/curtis54

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

    HB/curtis54

    Matrix properties (click for a legend)  
    number of rows54
    number of columns54
    structural full rank?yes
    structural rank54
    numerical rank 50
    dimension of the numerical null space4
    numerical rank / min(size(A))0.92593
    Euclidean norm of A 6.7242
    calculated singular value # 500.044184
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    4.7962e-014
    calculated singular value # 519.6733e-016
    gap in the singular values at the numerical rank:
    singular value # 50 / singular value # 51
    4.5676e+013
    calculated condition number9.5304e+016
    condestInf
    nonzeros291
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries0
    nonzero pattern symmetry 95%
    numeric value symmetry 95%
    typebinary
    structureunsymmetric
    Cholesky candidate?no
    positive definite?no

    authorA. Curtis
    editorA. Curtis, I. Duff, J. Reid
    date1971
    kind2D/3D problem
    2D/3D problem?yes
    SJid89
    UFid109

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))224 239
    Cholesky flop count9.8e+002 1.2e+003
    nnz(L+U), no partial pivoting394 424
    nnz(V) for QR, upper bound nnz(L) for LU266 304
    nnz(R) for QR, upper bound nnz(U) for LU556 565

    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.