• SJSU Singular Matrix Database
  • Matrix group: GHS_indef
  • Click here for a description of the GHS_indef group.
  • Click here for a list of all matrices
  • Click here for a list of all matrix groups

  • Matrix: GHS_indef/laser
  • Description: Gould, Hu, & Scott:
  • download as a MATLAB mat-file, file size: 35 KB. Use SJget(137) or SJget('GHS_indef/laser') in MATLAB.
  • download in Matrix Market format, file size: 14 KB.
  • download in Rutherford/Boeing format, file size: 13 KB.


    Routine svd from Matlab (R2008a) used to calculate the singular values.


    dmperm of GHS_indef/laser

    Matrix properties (click for a legend)  
    number of rows3,002
    number of columns3,002
    structural full rank?no
    structural rank3,000
    numerical rank 3,000
    dimension of the numerical null space2
    numerical rank / min(size(A))0.99933
    Euclidean norm of A 4.2491
    calculated singular value # 30000.22621
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    calculated singular value # 30015.9765e-016
    gap in the singular values at the numerical rank:
    singular value # 3000 / singular value # 3001
    calculated condition number9.2609e+016
    # of blocks from dmperm1,002
    # strongly connected comp.1
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    Cholesky candidate?yes
    positive definite?no

    editorN. Gould, Y. Hu, J. Scott
    kindmaterials problem
    2D/3D problem?yes

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))8,001 10,886
    Cholesky flop count2.2e+004 4.4e+004
    nnz(L+U), no partial pivoting13,000 18,770
    nnz(V) for QR, upper bound nnz(L) for LU7,993 11,881
    nnz(R) for QR, upper bound nnz(U) for LU14,996 22,555

    Maintained by Leslie Foster, last updated 24-Apr-2009.

    Entries 5 through 14 in the table of matrix properties and the singular
    value plot were created using SJsingular code. The other plots
    and statistics are produced using utilities from the SuiteSparse package.
    Matrix color plot pictures by cspy, a MATLAB function in the CSparse package.