Matrix: HB/well1850

Description: UNSYMMETRIC LEAST-SQUARES PROBLEM. SAUNDERS 1979.

HB/well1850 graph
(bipartite graph drawing)


HB/well1850 dmperm of HB/well1850

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  • Matrix group: HB
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  • download as a MATLAB mat-file, file size: 60 KB. Use UFget(261) or UFget('HB/well1850') in MATLAB.
  • download in Matrix Market format, file size: 61 KB.
  • download in Rutherford/Boeing format, file size: 53 KB.

    Matrix properties
    number of rows1,850
    number of columns712
    nonzeros8,755
    structural full rank?yes
    structural rank712
    # of blocks from dmperm10
    # strongly connected comp.1
    explicit zero entries3
    nonzero pattern symmetry 0%
    numeric value symmetry 0%
    typereal
    structurerectangular
    Cholesky candidate?no
    positive definite?no

    authorM. Saunders
    editorI. Duff, R. Grimes, J. Lewis
    date1979
    kindleast squares problem
    2D/3D problem?no

    Additional fieldssize and type
    bfull 1850-by-1

    Ordering statistics:result
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD83,883
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD9,021

    Note that all matrix statistics (except nonzero pattern symmetry) exclude the 3 explicit zero entries.

    SVD-based statistics:
    norm(A)1.79433
    min(svd(A))0.0161197
    cond(A)111.313
    rank(A)712
    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/well1850 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.