Matrix: HB/nnc261

Description: U NATIONAL NUCLEAR CORP. FISSION REACTOR SIESMIC STUDIES

HB/nnc261 graph HB/nnc261 graph
(bipartite graph drawing) (graph drawing of A+A')

HB/nnc261 dmperm of HB/nnc261

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  • Matrix group: HB
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  • download as a MATLAB mat-file, file size: 3 KB. Use UFget(215) or UFget('HB/nnc261') in MATLAB.
  • download in Matrix Market format, file size: 6 KB.
  • download in Rutherford/Boeing format, file size: 4 KB.

    Matrix properties
    number of rows261
    number of columns261
    nonzeros1,500
    structural full rank?yes
    structural rank261
    # of blocks from dmperm29
    # strongly connected comp.1
    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

    Ordering statistics:result
    nnz(chol(P*(A+A'+s*I)*P')) with AMD1,943
    Cholesky flop count1.8e+04
    nnz(L+U), no partial pivoting, with AMD3,625
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD3,118
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD6,593

    SVD-based statistics:
    norm(A)1040.63
    min(svd(A))3.5739e-12
    cond(A)2.91174e+14
    rank(A)260
    sprank(A)-rank(A)1
    null space dimension1
    full numerical rank?no
    singular value gap169.18

    singular values (MAT file):click here
    SVD method used:s = svd (full (A)) ;
    status:ok

    HB/nnc261 svd

    For a description of the statistics displayed above, click here.

    Maintained by Tim Davis, last updated 12-Mar-2014.
    Matrix pictures by cspy, a MATLAB function in the CSparse package.
    Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.