• 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 7.6.0.324 (R2008a) used to calculate the singular values. Matrix properties (click for a legend) number of rows 415 number of columns 415 structural full rank? yes structural rank 415 numerical rank 414 dimension of the numerical null space 1 numerical rank / min(size(A)) 0.99759 Euclidean norm of A 6.4719 calculated singular value # 414 0.022827 numerical rank defined using a tolerance max(size(A))*eps(norm(A)) = 3.6859e-013 calculated singular value # 415 4.4824e-016 gap in the singular values at the numerical rank: singular value # 414 / singular value # 415 5.0926e+013 calculated condition number 1.4438e+016 condest 1.042e+018 nonzeros 2,779 # of blocks from dmperm 1 # strongly connected comp. 1 entries not in dmperm blocks 0 explicit zero entries 0 nonzero pattern symmetry symmetric numeric value symmetry 65% type real structure unsymmetric Cholesky candidate? no positive definite? no

 author COMSOL editor T. Davis date 2003 kind 2D/3D problem 2D/3D problem? yes SJid 209 UFid 929

 Ordering statistics: AMD METIS nnz(chol(P*(A+A'+s*I)*P')) 4,539 4,920 Cholesky flop count 6.5e+004 7.7e+004 nnz(L+U), no partial pivoting 8,663 9,425 nnz(V) for QR, upper bound nnz(L) for LU 6,699 7,028 nnz(R) for QR, upper bound nnz(U) for LU 12,480 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.