# Want to use Matlab similar to Solver in Excel

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Krish on 20 Feb 2013
Answered: Alan Weiss on 25 Sep 2017
Hello, I am trying to use MATLAB to do what a solver in excel will be able to. I have a set of data I have collected experimentally (say Xexpt and Yexpt). I would like to use an *user defined non linear equation *( exponential equation relating y as a function of x but with two constants, A and B). I start with an initial guess value for A and B and calculate the corresponding Ycalc for each Xexpt value. I would like to minimize the square root of the sum of the difference in squares by changing the values of A and B. I could do this in excel by using Solver function, that minimizes the Sqrt (Sum (Yexpt^2-Ycalc^2)) by changing A and B. Can someone help me how i could do the same in Matlab ? Thanks in advance.
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guillaume de Guillebon on 21 Sep 2017
4.5 years later, but with the same problem. Did you find a solution for your problem ?

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### Answers (2)

Christoph F. on 21 Sep 2017
I think you're looking for the fminsearch() function.
Or alternatively something from the curve fitting toolbox.
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Christoph F. on 22 Sep 2017
lsqnonlin and related functions from the optimization toolbox might also be an option.

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Alan Weiss on 25 Sep 2017
For examples of how to do this with or without an Optimization Toolbox™ license, see Nonlinear Data-Fitting. To use Statistics Toolbox™, see Nonlinear Regression Workflow. Or check out Curve Fitting Toolbox.
Alan Weiss
MATLAB mathematical toolbox documentation
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