Re: [Maxima-discuss] gcl memory usage

[Robert D. <rob...@gm...>]

On 2018-04-23, David Scherfgen via Maxima-discuss <max...@li...> wrote:

> export GCL_MEM_MULTIPLE=0.2
>
> ... does what it is intended to do.
>
> According to his comment, this is supposed to influence the garbage
> collection behavior.
> But according to
> https://lists.gnu.org/archive/html/gcl-devel/2017-09/msg00000.html, this
> actually limits Maxima's total memory usage to 20% of RAM. On a system with
> 5 GB of RAM, Maxima will see only 1 GB.
>
> I don't think it's a good idea to artificially limit RAM usage. If need to
> work on a huge problem and have lots of RAM, I want Maxima to be able to
> make use of that RAM.

I haven't been following this topic closely. But in general, it's not
clear that making additional memory available to Maxima is really
helpful. In my experience, Maxima runs out of memory by attempting to
constructing a small number (maybe one) of enormous expressions.
Allocating additional memory would only make it possible to run longer
until that got used up too. 

I don't remember encountering problems with Maxima running out of memory
because I wanted to work on 10^9 small expressions and Maxima could only
handle 10^8 or something like that. 

That said, I don't know what is the optimal setting for memory
parameters for various implementations, and as always, YMMV.

best

Robert Dodier