how to print fval and optimised values at each iteration?

Hi I have a very simple task: printing fval and x values of each iteration. I already printed x values of each iteration, as mentioned in Outputfunction. However I have no luck printing fval of each iteration.

[Stephen23]

You defined the function, and each iteration provides the x values... why not just call the function with those values?

[King]

How should I call and save it in every iterative? Because I can't call it on myoutput, can't I? Sorry I'm very new to Matlab.

Answer 1

[Matt J]

Use the optimvalues structure to get fval, as described here

http://www.mathworks.com/help/matlab/math/output-functions.html#bsgpq6q-37

[King]

sadly replacing optimvalues with fval doesn't work, it only produce history of x values. Or I'm doing it wrong?

[Matt J]

I can't tell what you're doing. The link I gave you explains that the iterative solver will pass 3 variables to your Output Function

stop = outfun(x, optimValues, state)

optimValues is a structure that reports fval as one of its fields. So you can get fval from there and display it from your output Function just as you are doing for x.

[King]

okay, I can call optimValues alone. But why I can't call both x values and optimValues by rewriting like this

history = [history;x;optimValues];
and what should I write instead

[Matt J]

There are different things that you could do. My preference would be to make "history" a structure array

 optimValues.x=x;
 history = [history; optimValues];