Samples of Large-Memory Problems
Solved with ISETLW
If you have 8 MB of main memory, you probably also have 8 - 16 MBof virtual memory
(Windows swap file), but setting your ISETLW memory allocation much beyond the amount of
real memory can cause severe thrashing (swapping things in and out of real memory from virtual
memory on disk) when ISETLW is doing huge computations. I recommend using your real,
physical memory size as a maximum allocation. On an 8 MB machine you should be able to
do
!memory 8000000
On a 16 MB machine you should be OK doing
!memory 16000000
Try this with ISETL for DOS! (which won't let you actually use more than about
250-320K)
> !memory 12000000
Current GC memory = 50060, New Limit = 12000000
> #pow({1..15});
32768;
> !memory
Current GC memory = 4134956, Limit = 12000000
>
We actually used about 4 MB of memory to calculate the number of elements in the power set of
a set with 15 elements.
Last updated: December 27, 1995
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