• UF Sparse Matrix Collection
  • Matrix group: GHS_psdef
  • Click here for a description of the GHS_psdef group.
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  • Matrix: GHS_psdef/wathen120
  • Description: Gould,Higham,Scott: matrix from Andy Wathen, Oxford Univ.
  • download as a MATLAB mat-file, file size: 2 MB. Use UFget(1289) or UFget('GHS_psdef/wathen120') in MATLAB.
  • download in Matrix Market format
  • download in Rutherford/Boeing format

    GHS_psdef/wathen120

    GHS_psdef/wathen120 graph

    Matrix properties
    number of rows36,441
    number of columns36,441
    nonzeros565,761
    structural full rank?yes
    structural rank36,441
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    typereal
    structuresymmetric
    Cholesky candidate?yes
    positive definite?yes

    authorA. Wathen
    editorN. Gould, Y. Hu, J. Scott
    date2004
    kindrandom 2D/3D problem
    2D/3D problem?yes

    Notes:

    A = gallery('wathen',100,120) ; % (in MATLAB)                   
    To initialize the MATLAB random number generator to replicate   
    this matrix, first do the following:                            
    rand('state',0); A = gallery('wathen',100,100)                  
    and then generate this matrix using the 100,120 arguments above.
    

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))1,845,324 1,962,973
    Cholesky flop count2.5e+08 2.3e+08
    nnz(L+U), no partial pivoting3,654,207 3,889,505
    nnz(V) for QR, upper bound nnz(L) for LU3,750,470 3,400,133
    nnz(R) for QR, upper bound nnz(U) for LU8,902,766 7,785,789

    Maintained by Tim Davis, last updated 04-May-2008.
    Matrix pictures by cspy, a MATLAB function in the CSparse package.
    Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.