different PDEs to solve through events in pdepe

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feynman feynman 2024-2-8

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评论： feynman feynman 2024-2-8

There is a model defined by a pointwise PDE solving for u(x,t), i.e. it is PDE1 when u(x,t)>0 and PDE2 when u(x,t)<=0. Can one use pdepe events to solve this pointwise PDE? I don't think the following code works because once umesh=0 anywhere the whole PDE will be switched to the other (e.g. PDE2 on the global domain rather than locally will be triggered if PDE1 is terminated by events).

function [value, isterminal, direction] = pdevents(m,t,xmesh,umesh)
value = umesh;
isterminal = ones(size(umesh));
direction = zeros(size(umesh));

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Torsten 2024-2-8

Then you should try to manage these discontinuities within the function that defines the PDE equation, not by using the "events" facility.

"Events" might be useful in this context to stop an integration (e.g. if the PDE has reached a steady state or if some value has reached a certain limit level).

feynman feynman 2024-2-8