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F
FP_97650261-Visitor
1-Visitor
December 30, 2020
Question

Constraints using multidfit

  • December 30, 2020
  • 1 reply
  • 1526 views

 Hi everyone! 

I'm trying to fit a curve employing a multivariable function (5 variables and 5 parameters), which is a kinetic model. I could write the matrixes but the parameters are negative, and I need positive values. How can I write contraints for those parameters?

Here you'll find the file.

Thanks!

1 reply

W
Werner_E25-Diamond I
25-Diamond I
January 4, 2021

Multidfit is not part of a solve block but a stand alone function. This means that you cannot provide any constraints.

 

You may try a solve block with "minerr" to do the job.

Werner_E_0-1609792331595.png

As you can see the fit is not as good as the one without the constraints and Mathcad holds the last two vector elements of Gu hard at their limits (0 and 10).

 

MC15 worksheet attached

 

F
FP_97650261-VisitorAuthor
1-Visitor
January 6, 2021

Thank you very much! I can try employing different initial values. 

Best regards!

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