• UF Sparse Matrix Collection
  • Matrix group: Nasa
  • Click here for a description of the Nasa group.
  • Click here for a list of all matrices
  • Click here for a list of all matrix groups

  • Matrix: Nasa/pwt
  • Description: PWT: Nasa matrix, but with a diagonal added to the original matrix
  • download as a MATLAB mat-file, file size: 313 KB. Use UFget(762) or UFget('Nasa/pwt') in MATLAB.
  • download in Matrix Market format
  • download in Rutherford/Boeing format

    Nasa/pwt

    dmperm of Nasa/pwt

    Nasa/pwt graph

    Matrix properties
    number of rows36,519
    number of columns36,519
    nonzeros326,107
    structural full rank?yes
    structural rank36,519
    # of blocks from dmperm57
    # strongly connected comp.57
    entries not in dmperm blocks0
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    typebinary
    structuresymmetric
    Cholesky candidate?yes
    positive definite?no

    authorNASA
    editorG. Kumfert, A. Pothen
    date1995
    kindduplicate structural problem
    2D/3D problem?yes

    Notes:

    Nasa/pwt, GHS_psdef/pwt and Pothen/pwt are identical; Pothen/ has xyz coord.

    Ordering statistics:AMD METIS DMPERM+
    nnz(chol(P*(A+A'+s*I)*P'))1,555,833 1,382,606 1,379,004
    Cholesky flop count1.6e+08 1.1e+08 1.1e+08
    nnz(L+U), no partial pivoting3,075,147 2,728,693 2,721,489
    nnz(V) for QR, upper bound nnz(L) for LU2,667,503 2,306,419 2,278,609
    nnz(R) for QR, upper bound nnz(U) for LU5,000,519 4,342,072 4,289,181

    Maintained by Tim Davis, last updated 04-May-2008.
    Matrix pictures by cspy, a MATLAB function in the CSparse package.
    Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.