• 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/nnc261
  • Description: U NATIONAL NUCLEAR CORP. FISSION REACTOR SIESMIC STUDIES
  • download as a MATLAB mat-file, file size: 5 KB. Use SJget(161) or SJget('HB/nnc261') in MATLAB.
  • download in Matrix Market format, file size: 6 KB.
  • download in Rutherford/Boeing format, file size: 4 KB.

    HB/nnc261

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

    HB/nnc261

    dmperm of HB/nnc261

    Matrix properties (click for a legend)  
    number of rows261
    number of columns261
    structural full rank?yes
    structural rank261
    numerical rank 260
    dimension of the numerical null space1
    numerical rank / min(size(A))0.99617
    Euclidean norm of A 1040.6
    calculated singular value # 2606.0463e-010
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    5.9345e-011
    calculated singular value # 2613.6004e-012
    gap in the singular values at the numerical rank:
    singular value # 260 / singular value # 261
    167.93
    calculated condition number2.8903e+014
    condest1.1666e+015
    nonzeros1,500
    # of blocks from dmperm29
    # strongly connected comp.1
    entries not in dmperm blocks112
    explicit zero entries0
    nonzero pattern symmetry 82%
    numeric value symmetry 61%
    typereal
    structureunsymmetric
    Cholesky candidate?no
    positive definite?no

    authorNational Nuclear Corp.
    editorI. Duff, R. Grimes, J. Lewis
    date1982
    kind2D/3D problem
    2D/3D problem?yes
    SJid161
    UFid215

    Ordering statistics:AMD METIS DMPERM+
    nnz(chol(P*(A+A'+s*I)*P'))1,943 2,088 3,501
    Cholesky flop count1.8e+004 2.2e+004 6.5e+004
    nnz(L+U), no partial pivoting3,625 3,915 6,853
    nnz(V) for QR, upper bound nnz(L) for LU3,118 4,086 3,201
    nnz(R) for QR, upper bound nnz(U) for LU6,593 7,701 6,173

    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.