• 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/exdata_1
  • Description: MATRIX EXDATA FROM STEVE WRIGHT . MA57 SLOWER THAN MA27
  • download as a MATLAB mat-file, file size: 18 MB. Use SJget(518) or SJget('GHS_indef/exdata_1') in MATLAB.
  • download in Matrix Market format, file size: 7 MB.
  • download in Rutherford/Boeing format, file size: 6 MB.

    GHS_indef/exdata_1

    Routine svd from Matlab 7.6.0.324 (R2008a) used to calculate the singular values.

    GHS_indef/exdata_1

    Matrix properties (click for a legend)  
    number of rows6,001
    number of columns6,001
    structural full rank?yes
    structural rank6,001
    numerical rank 6,000
    dimension of the numerical null space1
    numerical rank / min(size(A))0.99983
    Euclidean norm of A 3.6957e+008
    calculated singular value # 60000.00039776
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    0.00035769
    calculated singular value # 60010.00034861
    gap in the singular values at the numerical rank:
    singular value # 6000 / singular value # 6001
    1.141
    calculated condition number1.0601e+012
    condest3.1673e+012
    nonzeros2,269,500
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries1
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    typereal
    structuresymmetric
    Cholesky candidate?no
    positive definite?no

    authorS. Wright
    editorN. Gould, Y. Hu, J. Scott
    date2004
    kindoptimization problem
    2D/3D problem?no
    SJid518
    UFid1,235

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))1,139,251 1,139,251
    Cholesky flop count1.1e+009 1.1e+009
    nnz(L+U), no partial pivoting2,272,501 2,272,501
    nnz(V) for QR, upper bound nnz(L) for LU1,139,251 1,139,251
    nnz(R) for QR, upper bound nnz(U) for LU5,640,751 7,890,751

    Note that all matrix statistics (except nonzero pattern symmetry) exclude the 1 explicit zero entries.

    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.