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Global constraint

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In the support knowledge Base Solution Number 1042 there is an example how to implement a Global constraint.

I just wanted to test this and created a 1-d convection and conduction model consisting out of one subdomain with the following boundaries:
Then I defined as described in the example under Options > Integration Coupling Variables > Boundary Variables the variable T_probe with the expression T (point 1 in the example).
Afterwords I defined the global equation Q_0: T_probe-320=0.

When I try to solve the problem the error 7111 Singular matrix appears.

What happens there?
Thanks for comments!

0 Replies Last Post 2009年9月2日 GMT+2 14:55
COMSOL Moderator

Hello Oliver Ottinger

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