Matrix: Um/offshore

Description: 3D FEM, transient electric field diffusion. Evan Um, Stanford

Um/offshore graph
(undirected graph drawing)


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  • download as a MATLAB mat-file, file size: 38 MB. Use UFget(2283) or UFget('Um/offshore') in MATLAB.
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  • download in Rutherford/Boeing format, file size: 29 MB.

    Matrix properties
    number of rows259,789
    number of columns259,789
    structural full rank?yes
    structural rank259,789
    # of blocks from dmperm1
    # strongly connected comp.1
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetrysymmetric
    Cholesky candidate?yes
    positive definite?yes

    authorE. Um
    editorT. Davis
    kindelectromagnetics problem
    2D/3D problem?yes

    Additional fieldssize and type
    bfull 259789-by-1


    This is a finite-element system matrix deriving from the 3D transient
    electric field diffusion equation. The matrix results from the       
    discretization of offshore conductivity structures using tetrahedral 
    elements.  Evan Um, Geophysics, Stanford.                            

    Ordering statistics:result
    nnz(chol(P*(A+A'+s*I)*P')) with AMD158,143,888
    Cholesky flop count4.6e+11
    nnz(L+U), no partial pivoting, with AMD316,027,987
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD392,939,742
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD744,604,111

    For a description of the statistics displayed above, click here.

    Maintained by Tim Davis, last updated 12-Mar-2014.
    Matrix pictures by cspy, a MATLAB function in the CSparse package.
    Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.