[Maxima] how to allocate more memory?
robert.dodier at gmail.com
Tue Jun 6 08:47:16 CDT 2006
On 6/6/06, Dan Hatton <vi5u0-maxima at yahoo.co.uk> wrote:
> Thanks for the advice. By "divide and conquer," do you mean
> something like:
> x^2+y = x/(1-y^2) ;
> solve(%, x) ;
> x : ev(x, %) ;
> (3*x+y^3)/(1+x) = x*y-x^3 ;
> solve(%, y) ;
> y : ev(y, %) ;
> Maxima has managed to come up with expressions for nine
> of the eleven variables I'm trying to solve for,
> and is currently working on the tenth. Still no sign of out-of-memory
> errors with the recompiled GCL.
Terrific! Perhaps I was needlessly pessimistic.
> I'm not inclined to give up on the current run yet:
> although Maxima has been running the calculation for
> four days, it's only applied about half an hour of CPU time to it,
> presumably because it's having to spend most of the time waiting for
> swap, due to the huge memory demand.
My advice here is to disable swap.
Using the disk as a big array has usually been a loss in
my experience. (Using it as a reserve for inactive programs
is a different question.)
Are you running Linux? One characteristic is that Linux
is deliberately optimistic about memory allocation.
This can easily lead to excessive swapping,
excessive meaning less work (none at all, in some cases)
gets done than if swapping were disabled.
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