How to find value of X when Y reaches maximum value

Hello,

I am new to MATLAB Simulink, I want output as the value of X when Y reaches maximum.

Y is a calculated value from an equation and is a function of X

[Rik]

Does it have to be inside Simulink, or is it also possible to move this problem to Matlab itself?

[RAHUL YADAV]

Rik, thanks for the reply

This model is in Simulink so it would be better if the answer is related to same..

But still I can use user defined function to use MATLAB code having X and Y axes as input...

[Rik]

I don't know much about Simulink, so I can't help you there. Once you have a function in Matlab itself you can use fminsearch. You want the maximum, so you would need to invert your function (inverted=@(varargin) -YourFunction(varargin{:});)

[RAHUL YADAV]

Thanks for the reply...

problem solved using Leonardo's approach

Answer 1

[Leonardo Maia]

Not sure what kind of output you want, but one way would be to get the derivative of your y(x) function. When it's "zero", it's at a maximum or minimum. I added quotes to "zero" because it's not going to be zero due to the time step of the solver. In the above example I'm getting the absolute of the derivative and when it's <= 0.01, I get the x value.

[RAHUL YADAV]

This helps...

Thanks

[RAHUL YADAV]

1) I got the zero crossing of y=f(x) (maxima)...

2) And after using the switch I am getting a spike at which the condition is approx zero

3)At last, what can I do get the output of value of X... like in this case ''displays 0.13.. something''

[Leonardo Maia]

I would try using the max block: https://www.mathworks.com/help/simulink/slref/find-max-value-of-input.html

[RAHUL YADAV]

Thanks

Answer 2

[Sara Boznik]

https://www.mathworks.com/help/symbolic/examples/maxima-minima-and-inflection-points.html

read about this

[RAHUL YADAV]

Thanks..