Problem with my function

I have a fitness function as shown below.

function z=sample_fit(r)
Flag=0;
while ~Flag
//take inputs from user
Flag=1;
end
//process the inputs

The above function is called for n times by a GA solver. The problem is that, use of flag in the function is useless as it is always set to zero on every iteration. I want the user to be requested for input only once in the first iteration and for rest of the iterations it will use the values provided in the first iteration.

Answer 1

[per isakson]

If in the first iteration the word, iteration, means call of the function, sample_fit, see persistent, Define persistent variable

[Febin Benjamin]

Per isakson, you mean like this?

function z=sample_fit(r)
persistent Flag;
Flag=0;
while ~Flag
//accept inputs from user
Flag=1;
end
//process inputs

[per isakson]

If you make a simple example to try this construct you will find that it doesn't work. Flag=0 (btw: I prefer Flag=false) will be executed every time; nothing achieved with persitent.

See first example in documentation of persistent. You need something like

    if isempty( Flag ) 
         Flag = false;
    end