# 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.
guillaume de Guillebon on 21 Sep 2017
4.5 years later, but with the same problem. Did you find a solution for your problem ?

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

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