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From: Eoin on 2 Jun 2010 12:47
Hi,

If I store a .wav file in a variable using wavread() the variable will use up some memory. When I'm finished with that .wav file I can clear the variable but if I want to use the variable again in the near future does setting it equal to 0 free up all the memory it was using, or should I really use clear?

Many Thanks
From: Walter Roberson on 2 Jun 2010 12:58
Eoin wrote:

> If I store a .wav file in a variable using wavread() the variable will
> use up some memory. When I'm finished with that .wav file I can clear
> the variable but if I want to use the variable again in the near future
> does setting it equal to 0 free up all the memory it was using, or
> should I really use clear?

Setting a variable to zero does not free up memory (unless the variable
was a sparse matrix.)
From: James Tursa on 2 Jun 2010 13:43
Walter Roberson <roberson(a)hushmail.com> wrote in message <C4wNn.85981$jt.66206(a)newsfe04.iad>...
> Eoin wrote:
>
> > If I store a .wav file in a variable using wavread() the variable will
> > use up some memory. When I'm finished with that .wav file I can clear
> > the variable but if I want to use the variable again in the near future
> > does setting it equal to 0 free up all the memory it was using, or
> > should I really use clear?
>
> Setting a variable to zero does not free up memory (unless the variable
> was a sparse matrix.)

To be clear (no pun intended), I think what you meant was setting the *contents* of a variable to zero does not free up memory. Setting a variable directly to 0 does free up memory because it implicitly does a clear on the old variable. e.g.,

A = some large array;
A(:) = 0; % sets contents to 0's, does not free up memory
A = 0; % clears the old A (frees memory) and sets a new A equal to a simple 0 scalar.

James Tursa
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