MATLAB Answers

Naty S
0

Sending a Function Handle to a Function

Asked by Naty S
on 7 May 2013

Hey all I am trying to a send a function handle to a different function. Inside the function handle i have a got a variable which i am changing every loop. The problem is that when i send the function handle to a different function the variable is no longer known to the sub-function.

for it = 1 : num
    ene(it)
BL.d=ene(it)*0.54;
dd=double(BL.d);
height=@(z)(dd);
height_str=func2str(height);
%     ene(it)    
%     retp
    if retp(2)~=inf,
    ret = fix_point(BL,ctrl,height_str, retp, period);
    end
end

So i get the following error

* |Undefined function or variable 'dd'.

Error in @(z)(dd)|*

Any suggestions? Thanks! Naty

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2 Answers

Answer by Walter Roberson
on 7 May 2013
 Accepted Answer

Where are you executing the function?

You are using func2str(), which changes the function handle to text, and you are passing the resulting string in to another routine. Are you evaluating that function string in the other routine? If you are then the conversion to string is what is doing you in: the reference to the variable is being converted to the name of the variable.

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Answer by Naty S
on 7 May 2013

So i can't send a string, must i send a function? That's where the error occurs:

function ret = bl_poincare_map(poin_sec,ctrl,height ,BowLeg, period)
fd=str2func(height);
d=fd(BowLeg.x(2));

Thanks for the response Naty

  1 Comment

Yes, you must send the function handle itself. Then if "height" is the function handle, invoke

 d = height(BowLeg.x(2))

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