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

  • Matrix: GHS_psdef/ford2
  • Description: Gould, Hu, & Scott: car surface mesh, from Pothen & Kumfert
  • download as a MATLAB mat-file, file size: 904 KB. Use SJget(482) or SJget('GHS_psdef/ford2') in MATLAB.
  • download in Matrix Market format, file size: 852 KB.
  • download in Rutherford/Boeing format, file size: 799 KB.


    A singular value of A is guaranteed1 to be in the interval pictured by the blue bars around each of the calculated singular values.

    Routine svds_err, version 1.0, used with Matlab (R2008a) to calculate the 6 largest singular values and associated error bounds.
    Routine spnrank, version 1.0, used with Matlab (R2008a) to calculate singular values 97890 to 97895 and associated error bounds.


    Matrix properties (click for a legend)  
    number of rows100,196
    number of columns100,196
    structural full rank?yes
    structural rank100,196
    numerical rank 97,892
    dimension of the numerical null space2,304
    numerical rank / min(size(A))0.97701
    Euclidean norm of A 27.16
    calculated singular value # 978927.4952e-006
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    calculated singular value # 978931.7515e-015
    gap in the singular values at the numerical rank:
    singular value # 97892 / singular value # 97893
    calculated condition number-2
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    Cholesky candidate?yes
    positive definite?no

    authorG. Kumfert, A. Pothen
    editorN. Gould, Y. Hu, J. Scott
    kindstructural problem
    2D/3D problem?yes

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))2,378,217 2,353,448
    Cholesky flop count2.9e+008 2.2e+008
    nnz(L+U), no partial pivoting4,656,238 4,606,700
    nnz(V) for QR, upper bound nnz(L) for LU6,147,771 5,102,101
    nnz(R) for QR, upper bound nnz(U) for LU11,610,612 9,544,588

    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.