There are no memory leaks in the J interpreter.
(Never has from day 0.) Checkpoints are placed
in various places so that memory use is snapshot
on entry into a module and restored on exit
(except for those marked as "permanent" by things
such as the copula). In particular, there is
an overall checkpoint on the top-level immediate
execution module.
What happen in this case is that you used a lot
of small memory blocks, as indicated by
7!:3''
64 29644938
128 1293
256 342
512 270
1024 84
That is, there were about 30 million blocks of
size 64 bytes (= 1.9 G). The routine to free
up these memory blocks itself got an "out of
memory" error and was not able to do its work.
I'll fix this for the next release.
----- Original Message -----
From: Don Guinn <[EMAIL PROTECTED]>
Date: Friday, March 23, 2007 7:34 am
Subject: [Jprogramming] Out of Memory
> What follows is the entire contents of a J session which ran out
> of memory.
> This is on a 1G machine on Windows XP Pro.
>
> I was playing with one of the Project Euler problems and wanted to
> verifythe answer using rationals instead of floats. The solution
> using floats ran
> in about a second. When I converted it to use rationals it went to
> pagingand eventually ran out of memory. Fair enough. This is a
> pretty memory
> intensive approach.
>
> The problem is that once it ran out of memory nothing of any
> consequenceworked. Even clicking File/Exit got out of memory.
> Fortunately 7!:3''
> worked, but it took a long time to run as it had to go through a
> lot of
> memory that was paged.
>
> The thing is that there should be plenty of memory available as
> nothingbeyond the standard libraries were loaded. Is there a
> memory leak somewhere?
> Is it possible that when an out of memory occurs that J forgets to
> free up
> memory? This is on j601/2006-11-17/17:05
>
> x:(x:^:_1]3r7)(_2:{[:(/:~)[:~.]%~[:<.*)>:i.100000
> 42857r100000
> x:(x:^:_1]3r7)(_2:{[:(/:~)[:~.]%~[:<.*)>:i.1000000
> 428570r999997
> x:(x:^:_1]3r7)(_2:{[:(/:~)[:~.]%~[:<.*)>: i.1000000
> 428570r999997
> 3r7(_2:{[:(/:~)[:~.]%~[:<.*)>:i.1000000
> |out of memory
> | (_2:{[:(/:~)[:~.]%~[:<.*)>:i.1000000
> x:(x:^:_1]3r7)(_2:{[:(/:~)[:~.]%~[:<.*)>:i.1000000
> |out of memory
> | x:(x:^:_1]3r7) (_2:{[:(/:~)[:~.]%~[:<.*)>:i.1000000
>
> |out of memory: wdhandler_0_
> | wdq=: wd'q'
>
> |out of memory: wdhandler_0_
> | wdq=: wd'q'
>
> |out of memory: wdhandler_0_
> | wdq=: wd'q'
>
> |out of memory: wdhandler_0_
> | wdq=: wd'q'
>
> |out of memory: wdhandler_0_
> | wdq=: wd'q'
> 7!:3''
> 64 29644938
> 128 1293
> 256 342
> 512 270
> 1024 84
>
> |out of memory: wdhandler_0_
> | wdq=: wd'q'
>
> -------At this point after I copied the session to the clipboard
> for pasting
> into this message I entered 2!:55'' and ended the session.
----------------------------------------------------------------------
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