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MATPDE: Partial Differential Equation

from the NEP Collection

Matrix Generator MATPDE
Source: H. Elman, University of Maryland
Discipline: Partial differential equations
Language: Fortran
Output format: compressed row

This generator computes a five-point central finite difference discretization of the two-dimensional variable-coefficient linear elliptic equation -(p ux)x -(q uy)y + r ux + (r u)x + s uy + (s u)y + t u = f, where p, q, r, s and t are the functions of x and y. The domain is the unit square (0,1)x(0,1), and the boundary condition are Dirichlet.

Although the code handles arbitrary p, q, r, s and t, it is set up initially with p = exp(-xy), Q = exp(xy), R = beta (x+y), S = gamma (x+y), and t = 1/(1+x+y). It is suggested to use values of beta and gamma between 0 and 250. The object is to estimate those eigenvalues with the largest real parts and to determine whether or not there are significant gaps in the spectrum.


NXnumber of grid points along x axis
NYnumber of grid points along y axis
BETAcoefficient multiplying ux terms
GAMMAcoefficient multiplying uy terms


Matrix Instances:

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Last change in this page: Wed Sep 22 13:37:29 US/Eastern 2004 [Comments: ]