Matrix: HB/watt_2

Description: UNSYMMETRIC MATRIX FROM JOHN SOMERVILLE, HERIOT-WATT. DEC,1983 H

HB/watt_2 graph HB/watt_2 graph
(bipartite graph drawing) (graph drawing of A+A')


HB/watt_2 dmperm of HB/watt_2

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  • Matrix group: HB
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  • download as a MATLAB mat-file, file size: 80 KB. Use UFget(259) or UFget('HB/watt_2') in MATLAB.
  • download in Matrix Market format, file size: 76 KB.
  • download in Rutherford/Boeing format, file size: 64 KB.

    Matrix properties
    number of rows1,856
    number of columns1,856
    nonzeros11,550
    structural full rank?yes
    structural rank1,856
    # of blocks from dmperm65
    # strongly connected comp.65
    explicit zero entries0
    nonzero pattern symmetry 98%
    numeric value symmetry 97%
    typereal
    structureunsymmetric
    Cholesky candidate?no
    positive definite?no

    authorJ. Somerville
    editorI. Duff, R. Grimes, J. Lewis
    date1983
    kindcomputational fluid dynamics problem
    2D/3D problem?yes

    Ordering statistics:result
    nnz(chol(P*(A+A'+s*I)*P')) with AMD56,222
    Cholesky flop count3.7e+06
    nnz(L+U), no partial pivoting, with AMD110,588
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD113,884
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD208,447

    SVD-based statistics:
    norm(A)8
    min(svd(A))5.87021e-11
    cond(A)1.36281e+11
    rank(A)1,856
    sprank(A)-rank(A)0
    null space dimension0
    full numerical rank?yes

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

    HB/watt_2 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.