COMSOL Multiphysics™

postglobaleval
Purpose
postglobaleval
Evaluate globally defined expressions, such as solutions to ODEs.
Syntax
Description
data = postglobaleval(fem,...)
data = postglobaleval(fem,expr,...)
postglobaleval(fem,expr,...) is the evaluation function for globally defined
expressions, such as ODE solution variables.
The input expr contains the expressions to plot. It must be a cell array of strings. If
omitted, the expressions in fem.ode.dim are evaluated.
data = postglobaleval(fem,...) returns a structure with fields x, y, and legend.
This structure is compatible with the import/export structure used by COMSOL
Reaction Engineering Lab. The values can be plotted with
plot(data.x, data.y)
legend(data.legend)
Valid property/value pairs for postglobaleval are given in the following table.
TABLE 1-26: VALID PROPERTY/VALUE PAIRS
PROPERTY NAME PROPERTY VALUE DEFAULT DESCRIPTION
Const cell array Definition of constants
Phase scalar 0 Phase angle
Solnum integer vector | all | all
Solution number
end
T vector Times for evaluation
U
solution object or
vector
fem.sol or 0 Solution for evaluation
The property Phase is described in posteval.
Examples
Example: Solve the Lotka-Volterra equations for two populations r and f
clear fem
fem.ode.dim={'r','f'};
fem.ode.f={'r*(1-2*f)-rt','-f*(3-r)-ft'};
fem.ode.init={'10','1'};
fem.ode.dinit={'0','0'};
fem.geom=solid1([0,1]);
fem.mesh = meshinit(fem);
fem.xmesh = meshextend(fem);
fem.sol = femtime(fem,'tlist',[0,1]);
% Evaluate 'r' and 'f' for all time steps
data = postglobaleval(fem);
338 | CHAPTER 1: COMMAND REFERENCE