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

  • Matrix: JGD_SPG/EX1
  • Description: Symmetric powers of graphs from Gordon Royle, Univ Western Australia
  • download as a MATLAB mat-file, file size: 17 KB. Use SJget(608) or SJget('JGD_SPG/EX1') in MATLAB.
  • download in Matrix Market format, file size: 12 KB.
  • download in Rutherford/Boeing format, file size: 9 KB.


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


    Matrix properties (click for a legend)  
    number of rows560
    number of columns560
    structural full rank?yes
    structural rank560
    numerical rank 547
    dimension of the numerical null space13
    numerical rank / min(size(A))0.97679
    Euclidean norm of A 15.835
    calculated singular value # 5470.21585
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    calculated singular value # 5481.9964e-015
    gap in the singular values at the numerical rank:
    singular value # 547 / singular value # 548
    calculated condition number4.1335e+017
    # 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?unknown

    authorG. Royle
    editorJ.-G. Dumas
    kindcombinatorial problem
    2D/3D problem?no


    Symmetric powers of graphs from Gordon Royle, Univ Western Australia
    From Jean-Guillaume Dumas' Sparse Integer Matrix Collection,        
    Filename in JGD collection: SPG/EX1.sms                             

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))75,578 71,393
    Cholesky flop count1.7e+007 1.4e+007
    nnz(L+U), no partial pivoting150,596 142,226
    nnz(V) for QR, upper bound nnz(L) for LU101,807 98,209
    nnz(R) for QR, upper bound nnz(U) for LU134,426 137,501

    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.