Matrix: HB/str_400

Description: UNSYMMETRIC BASIS FROM LP PROBLEM STAIR

HB/str_400 graph HB/str_400 graph
(bipartite graph drawing) (graph drawing of A+A')

HB/str_400 dmperm of HB/str_400
scc of HB/str_400

  • Home page of the UF Sparse Matrix Collection
  • 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
  • download as a MATLAB mat-file, file size: 18 KB. Use UFget(256) or UFget('HB/str_400') in MATLAB.
  • download in Matrix Market format, file size: 16 KB.
  • download in Rutherford/Boeing format, file size: 13 KB.

    Matrix properties
    number of rows363
    number of columns363
    nonzeros3,157
    structural full rank?yes
    structural rank363
    # of blocks from dmperm203
    # strongly connected comp.2
    explicit zero entries0
    nonzero pattern symmetry 2%
    numeric value symmetry 0%
    typereal
    structureunsymmetric
    Cholesky candidate?no
    positive definite?no

    authorM. Saunders
    editorA. Curtis, I. Duff, J. Reid
    date1978
    kindsubsequent optimization problem
    2D/3D problem?no

    Notes:

    next: HB/str_600 first: HB/str_0

    Ordering statistics:result
    nnz(chol(P*(A+A'+s*I)*P')) with AMD16,655
    Cholesky flop count1.5e+06
    nnz(L+U), no partial pivoting, with AMD32,947
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD3,671
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD7,571

    SVD-based statistics:
    norm(A)14.6088
    min(svd(A))0.00227172
    cond(A)6430.7
    rank(A)363
    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/str_400 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.