GHS_indef/c-55 graph

Matrix: GHS_indef/c-55

Description: Schenk: IBM TJ Watson, Yorktown, nonlinear optimization


  • UF Sparse Matrix Collection
  • Matrix group: GHS_indef
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  • download as a MATLAB mat-file, file size: 2 MB. Use UFget(1220) or UFget('GHS_indef/c-55') in MATLAB.
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    GHS_indef/c-55

    Matrix properties
    number of rows32,780
    number of columns32,780
    nonzeros403,450
    structural full rank?yes
    structural rank32,780
    # 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?no
    positive definite?no

    authorIBM
    editorO. Schenk
    date2004
    kindoptimization problem
    2D/3D problem?no

    Additional fieldssize and type
    bfull 32780-by-1

    Notes:

    Revised Nov 2006; relative eps changes to A, right-hand-side added.
    Note that this matrix should have been placed in the Schenk_IBMNA/ 
    directory when it was first added in August 2004, but moving it now
    would disrupt exising users of the collection.                     
    

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))4,586,486 3,357,552
    Cholesky flop count5.4e+09 2.3e+09
    nnz(L+U), no partial pivoting9,140,192 6,682,324
    nnz(V) for QR, upper bound nnz(L) for LU22,834,246 17,908,333
    nnz(R) for QR, upper bound nnz(U) for LU39,659,082 35,034,134

    Maintained by Tim Davis, last updated 30-Sep-2008.
    Matrix pictures by cspy, a MATLAB function in the CSparse package.
    Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.