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

  • Matrix: Gleich/wb-cs-stanford
  • Description: Stanford CS web, A(i,j)=1 if page i links to page j (2001)
  • download as a MATLAB mat-file, file size: 119 KB. Use SJget(319) or SJget('Gleich/wb-cs-stanford') in MATLAB.
  • download in Matrix Market format, file size: 90 KB.
  • download in Rutherford/Boeing format, file size: 68 KB.


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


    scc of Gleich/wb-cs-stanford

    Matrix properties (click for a legend)  
    number of rows9,914
    number of columns9,914
    structural full rank?no
    structural rank5,782
    numerical rank 5,475
    dimension of the numerical null space4,439
    numerical rank / min(size(A))0.55225
    Euclidean norm of A 38.377
    calculated singular value # 54750.0010312
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    calculated singular value # 54761.4367e-013
    gap in the singular values at the numerical rank:
    singular value # 5475 / singular value # 5476
    calculated condition numberInf
    # of blocks from dmperm797
    # strongly connected comp.4,391
    explicit zero entries0
    nonzero pattern symmetry 46%
    numeric value symmetry 46%
    Cholesky candidate?no
    positive definite?no

    authorD. Gleich
    editorT. Davis
    kinddirected graph
    2D/3D problem?no


    For nodenames, see http://www.cise.ufl.edu/research/sparse/aux/Gleich
    This graph is a subset of Gleich/wb-edu, with *.cs.stanford.edu only.

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))58,395 67,470
    Cholesky flop count1.4e+006 2.1e+006
    nnz(L+U), no partial pivoting106,876 125,026
    nnz(V) for QR, upper bound nnz(L) for LU369,385 119,078
    nnz(R) for QR, upper bound nnz(U) for LU297,036 281,731

    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.