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Constraint Priority

zredey
1-Newbie

Constraint Priority

Hello all!

I am working on a problem in MathCAD 15.0. I am Trying to find the solution to a system of inequations

I am using the given...find() block

I have successfully defined my constants, functions and constraints and at the end of the block I get some result which is partially good with the stress on partially.

I have several constraints and some of them mgiht be contradictive. I was prepared that the set of constraints that I have defined could yield a "no solution found" but the solver gave me a solution instead which does not fulfill all constraints.

Unfortunately I cannot share my work but this attached picture demonstrates my problem quite well.solver.PNG

My questions are therefore:

  • What determines which constraints are kept and which will be violated? (I tried moving the contraint around to see if the order matters but I had no luck)
  • Is there a way to control the priority of contraints? (e.g.: create hard and soft requirements)
  • Is there a way to disable priorities (i.e.: every contraint must be fulfilled or no solution should be returned)?

Thank you for your kind support in advance!

1 ACCEPTED SOLUTION

Accepted Solutions
StuartBruff
23-Emerald II
(To:zredey)

Try adjusting the system variables TOL and/or CTOL.

See the Help on Find.

Stuart

View solution in original post

3 REPLIES 3
StuartBruff
23-Emerald II
(To:zredey)

Try adjusting the system variables TOL and/or CTOL.

See the Help on Find.

Stuart

It was indeed CTOL.

I somehow interpreted it to be a relative and not absolute number.

The CTOL=0.001 was therefore obviously too large for a constraint of I>1mA

Now I do get "no result".

StuartBruff
23-Emerald II
(To:zredey)

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