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

  • Matrix: Pothen/sphere3
  • Description: sphere3, with coordinates. From NASA, collected by Alex Pothen
  • download as a MATLAB mat-file, file size: 5 KB. Use SJget(219) or SJget('Pothen/sphere3') in MATLAB.
  • download in Matrix Market format, file size: 4 KB.
  • download in Rutherford/Boeing format, file size: 3 KB.


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


    Pothen/sphere3 graph

    Matrix properties (click for a legend)  
    number of rows258
    number of columns258
    structural full rank?yes
    structural rank258
    numerical rank 253
    dimension of the numerical null space5
    numerical rank / min(size(A))0.98062
    Euclidean norm of A 6.9725
    calculated singular value # 2530.047572
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    calculated singular value # 2544.6123e-016
    gap in the singular values at the numerical rank:
    singular value # 253 / singular value # 254
    calculated condition number7.417e+016
    # 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

    editorG. Kumfert, A. Pothen
    kindstructural problem
    2D/3D problem?yes

    Additional fieldssize and type
    coordfull 258-by-3

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))4,467 4,201
    Cholesky flop count1.1e+005 9.1e+004
    nnz(L+U), no partial pivoting8,676 8,144
    nnz(V) for QR, upper bound nnz(L) for LU5,191 5,768
    nnz(R) for QR, upper bound nnz(U) for LU9,301 10,052

    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.