Problem with my function

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Febin Benjamin
Febin Benjamin 2014-7-9
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.

回答(1 个)

per isakson
per isakson 2014-7-9
If in the first iteration the word, iteration, means call of the function, sample_fit, see persistent, Define persistent variable
  2 个评论
Febin Benjamin
Febin Benjamin 2014-7-9
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
per isakson 2014-7-9
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

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