Re: Loops resource usage.

[David Grohmann]

Muthiah Annamalai wrote:

Hello there,

I wanted to ask if there is a difference between writing a program like

for x=linspace(-pi:+pi,Npts)
   [X,Y,Z,L,M,N]=init_variables();
   do_a_time_consuming_long_computation();
 
  %clear the memory used
 
   clear all
end

% and this function?

for x=linspace(-pi:+pi,Npts)
   [X,Y,Z,L,M,N]=init_variables();
   do_a_time_consuming_long_computation();
end


My advisor told me, it saves something and does better in long programs.
Thanks in advance.

Thanks,
Muthu
PS: I couldnt find anything useful on this topic, in a Gmane search

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I'm not too familiar with octave's internals but what you are basically saying is

start loop; do stuff; clear memory; loop back

versus

start loop; do stuff; loop back (implied that the octave reference counter/garbage collector will clear the memory for you in this case)

either way memory will be reclaimed when needed, I suspect doing a manual clear would actually slow things down, since you wont be able to amortize the garbage collection cost of more loop iterations.


I suppose the real answer is benchmark it and let us know which is faster.

-- 
David Grohmann
Senior Student Associate
Applied Research Lab : UT Austin : ESL - S206
Office: 512-835-3237