Problem Description

Solution

Yes, you can. The easiest way is to use the daspk solver from the COMSOL Script command line. This is a solver for

• Systems of ordinary differential equations (ODEs)
• Mixed systems of differential and algebraic equations (DAEs)

For the special case when all time derivatives are zero, we get an algebraic, possibly nonlinear, equation system. Here is an example:

With x=2.5, y=6 as start guesses, the code

f = inline('[y(1)^2+3*y(2)^2-84 3*y(1)+log(y(2))-10.609]','t','y');
[t y] = daspk(f, [0 1], [2.5 6], odeset('Mass', zeros(2)));
y(end, :)

Generates the output

ans =

2.9999     5.0000

For more information, see help daspk.

See also: Solution 1007 for solution of algebraic equations in the COMSOL Multiphysics GUI, for coupled Algebraic-ODE-PDE systems.

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