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

  • Matrix: FEMLAB/problem1
  • Description: Comsol, Inc. www.femlab.com : small test problem
  • download as a MATLAB mat-file, file size: 24 KB. Use SJget(209) or SJget('FEMLAB/problem1') in MATLAB.
  • download in Matrix Market format, file size: 28 KB.
  • download in Rutherford/Boeing format, file size: 27 KB.


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


    Matrix properties (click for a legend)  
    number of rows415
    number of columns415
    structural full rank?yes
    structural rank415
    numerical rank 414
    dimension of the numerical null space1
    numerical rank / min(size(A))0.99759
    Euclidean norm of A 6.4719
    calculated singular value # 4140.022827
    numerical rank defined using a tolerance
    max(size(A))*eps(norm(A)) =
    calculated singular value # 4154.4824e-016
    gap in the singular values at the numerical rank:
    singular value # 414 / singular value # 415
    calculated condition number1.4438e+016
    # of blocks from dmperm1
    # strongly connected comp.1
    entries not in dmperm blocks0
    explicit zero entries0
    nonzero pattern symmetrysymmetric
    numeric value symmetry 65%
    Cholesky candidate?no
    positive definite?no

    editorT. Davis
    kind2D/3D problem
    2D/3D problem?yes

    Ordering statistics:AMD METIS
    nnz(chol(P*(A+A'+s*I)*P'))4,539 4,920
    Cholesky flop count6.5e+004 7.7e+004
    nnz(L+U), no partial pivoting8,663 9,425
    nnz(V) for QR, upper bound nnz(L) for LU6,699 7,028
    nnz(R) for QR, upper bound nnz(U) for LU12,480 12,982

    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.