Matrix: HB/young4c

Description: complex matrix from aero research, David Young, corrected CUA version

HB/young4c graph
(undirected graph drawing)


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  • Matrix group: HB
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  • download as a MATLAB mat-file, file size: 8 KB. Use UFget(281) or UFget('HB/young4c') in MATLAB.
  • download in Matrix Market format, file size: 13 KB.
  • download in Rutherford/Boeing format, file size: 10 KB.

    Matrix properties
    number of rows841
    number of columns841
    structural full rank?yes
    structural rank841
    # of blocks from dmperm1
    # strongly connected comp.1
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetry 80%
    Cholesky candidate?no
    positive definite?no

    authorD. Young
    editorI. Duff, R. Grimes, J. Lewis
    kindacoustics problem
    2D/3D problem?yes


    The YOUNG*C matrices originally appeared in the Harwell/Boeing     
    collection as type CSA (complex symmetric).  However, both upper   
    and lower triangular parts are present in the original files       
    (an invalid specification; only the lower part can be present      
    in the file).  If the entries in the upper triangular part are     
    considered as part of the matrix, the matrices become unsymmetric. 
    The matrices have been corrected in the UF Sparse Matrix Collection
    by changing their type to CUA so that the entries in the original  
    files are not ignored.  In addition, the YOUNG3C matrix has a zero 
    imaginary part, and thus appears here as a real matrix.            

    Ordering statistics:result
    nnz(chol(P*(A+A'+s*I)*P')) with AMD9,198
    Cholesky flop count1.6e+05
    nnz(L+U), no partial pivoting, with AMD17,555
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD15,517
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD27,859

    SVD-based statistics:
    null space dimension0
    full numerical rank?yes

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

    HB/young4c 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.