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

  • Matrix: Hohn/fd18
  • Description: M. Hohn, Univ Utah. Single-material crack problem, finite diff log grid
  • download as a MATLAB mat-file, file size: 174 KB. Use SJget(396) or SJget('Hohn/fd18') in MATLAB.
  • download in Matrix Market format, file size: 299 KB.
  • download in Rutherford/Boeing format, file size: 238 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 16354 to 16359 and associated error bounds.


    dmperm of Hohn/fd18

    Matrix properties (click for a legend)  
    number of rows16,428
    number of columns16,428
    structural full rank?yes
    structural rank16,428
    numerical rank 16,356
    dimension of the numerical null space72
    numerical rank / min(size(A))0.99562
    Euclidean norm of A 7.2893e+008
    calculated singular value # 163560.0020102
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    calculated singular value # 163570.0019096
    gap in the singular values at the numerical rank:
    singular value # 16356 / singular value # 16357
    calculated condition number-2
    # of blocks from dmperm1,061
    # strongly connected comp.1
    entries not in dmperm blocks1,859
    explicit zero entries0
    nonzero pattern symmetry 0%
    numeric value symmetry 0%
    Cholesky candidate?no
    positive definite?no

    authorM. Hohn
    editorT. Davis
    kindmaterials problem
    2D/3D problem?yes

    Additional fieldssize and type
    bfull 16428-by-1

    Ordering statistics:AMD METIS DMPERM+
    nnz(chol(P*(A+A'+s*I)*P'))8,300,663 13,612,979 648,420
    Cholesky flop count1.5e+010 2.9e+010 7.1e+007
    nnz(L+U), no partial pivoting16,584,898 27,209,530 1,282,271
    nnz(V) for QR, upper bound nnz(L) for LU766,230 617,644 632,463
    nnz(R) for QR, upper bound nnz(U) for LU1,452,963 1,270,956 1,235,890

    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.