• 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

  • Matrix: HB/young1c
  • Description: complex matrix from aero research, David Young, corrected CUA version
  • download as a MATLAB mat-file, file size: 8 KB. Use UFget(278) or UFget('HB/young1c') in MATLAB.
  • download in Matrix Market format
  • download in Rutherford/Boeing format

    HB/young1c

    HB/young1c graph

    Matrix properties
    number of rows841
    number of columns841
    nonzeros4,089
    structural full rank?yes
    structural rank841
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetry 85%
    typecomplex
    structureunsymmetric
    Cholesky candidate?no
    positive definite?no

    authorD. Young
    editorI. Duff, R. Grimes, J. Lewis
    date1984
    kindacoustics problem
    2D/3D problem?yes

    Notes:

    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:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))9,198 10,511
    Cholesky flop count1.6e+05 2.3e+05
    nnz(L+U), no partial pivoting17,555 20,181
    nnz(V) for QR, upper bound nnz(L) for LU15,517 16,340
    nnz(R) for QR, upper bound nnz(U) for LU27,859 29,571

    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.