memory

pagan — Sat, 19 Dec 2009 07:51:04 Z

Perhaps it ran out of memory on your machine but not on his machine.

Or perhaps it could not allocate enough memory due to a restriction in your operating system's shell. You might try launching Maple (Standard GUI or commandline interface, your choice) from a commandline terminal window on your Mac. You could first issue `ulimit -d <value>` in that shell, where <value> represented at least as much memory space as was used by Maple in your friends successful run.

Maybe see also here.

Out of memory exception

dohashi — Tue, 22 Dec 2009 23:53:13 Z

You will get this exception when your operating system refuses to give Maple more memory. There are a few different scenarios when this can happen. The most common one is that Maple is consuming all the memory on your machine. Eventually you will run out of memory. Another possibility (and this is more likely on Mac/Unix than it is on windows) is that the operating system is imposing a memory limit on the Maple kernel, and Maple has used all that memory. Finally, it is possible that Maple is trying to allocate a single huge object, say 10^(10^10).

You can see how much memory Maple thinks it has access to but calling kernelopts( datalimit ).

> kernelopts( datalimit );
1482000

The return value is in kilobytes (well kibibytes technically).

If the return value is "infinity", then Maple thinks it has no limits (except the total memory available on the system).

If the limit is much lower than the total amount of RAM on your machine, then you probably have a OS imposed memory limit. One of the comments on the post that pagan linked to describes how to fix that on the Mac.

Darin

-- Kernel Developer Maplesoft

Same problem, and a little more insight...

daryljanzen — Tue, 26 Jan 2010 08:55:19 Z

This appears to be my problem. Unfortunately, I couldn't get it to work out from these suggestions. I am running Mac OSX Version 10.5.8, I have 4GB of RAM, and I am using Maple 13. When I run a calculation, the `Memory' indicator at the bottom cuts out just below 200M (whatever that means; I don't think it's mebibytes), whereas a handy program I have just installed, called `MenuMeters', confirms that the calculation is aborting once it reaches about 400 mebibytes. Note that kernelopts(datalimit) outputs `409600' (which seems to be Maple's default setting?).

Anyway, I have tried altering the files as this, and the linked page indicate, but nothing has changed when I run Maple. There is a difference that may be new with Maple 13: The line that seems to have begun with,

ulimit -d 524288 || ulimit -d 409600 || ulimit -d 307200

to be changed to something like,

ulimit -d 1000000 || ulimit -d 409600 || ulimit -d 307200

is now

ulimit -d unlimited > /dev/null 2>&1 || ulimit -d 524288 > /dev/null 2>&1 || ulimit -d 409600 > /dev/null 2>&1 || ulimit -d 307200 > /dev/null 2>&1
ulimit -s 65536 > /dev/null 2>&1 || ulimit -s 32768 > /dev/null 2>&1 || ulimit -s 16384 > /dev/null 2>&1

I changed the number that was indicated (524288 to 2524288) and saved the file. Then I ran it with Terminal (which wasn't suggested), but I still can't go beyond kernalopts(datalimit); 409600 when I open Maple.

However, I just had an idea which has shed some major light on this issue. I opened both mserver_ulimit and mserver_ulimit32 with my text editor and changed 409600 to 409500, saved, and ran both of them in Terminal. This changed the output of kernalopts(datalimit) to 409500. This changes the hard limit, so that kernelopts(datalimit=409600) gives the error message

Error, cannot raise the datalimit above the hard limit

So I've made some headway. Changing this value to 409700 produces the same result. After some time, I have made the important discovery: My OS is imposing a limit of 512000 mebibytes, which cannot be got around. When I change 409600 to 512000 in the default line I've printed above, it works, but when I change it to 512001, the OS will not allow that, so Maple takes the next value down the line; 307200. This is why changing the value of 524288 to anything larger does nothing for me---it is already too large for system constraints, so the next best value (409600) was already being taken.

So now I have narrowed this down to an operating system issue.

The previous help files should not be useful for anyone whose OS is limited as mine is, because increasing the value of an already-too-large number does nothing; this is already covered in Maple 13 by including an initial value of `unlimited', which some operating systems might accept. Some other OSs, like mine, only allow for 0.5GiB per application, although I can't find a statement of this anywhere on the web. I will have to contact Apple and get back to this thread if I make any headway there.

I should note again, for clarity, one important step which is missing in the previous instructions on how to increase this `hard limit' to the value dictated by OS constraints:

1. Right click on mserver_ulimit or mserver_ulimit32 and open with a text editor. (change to Read & Write if you have to).

2. Change the value which is limiting your allowed memory (you should check this first in Maple with kernelopts(datalimit)) to as high as your operating system will allow (you may have to determine this value through trial and error, but if one exists it should be some power of 2). Save the file and close it.

3. Double-click on mserver_ulimit (or mserver_ulimit32). It will run in Terminal. Close that.

4. Make sure Maple is not running. Open Maple and type kernelopts(datalimit). The output should be your specified limit.

Step 3 is important, because without doing this, Maple won't know that you've changed the value. I believe this is related to what is mentioned in the link that pagan posted.

If I find out anything from Apple, I will post that solution.

solution

daryljanzen — Thu, 28 Jan 2010 00:25:04 Z

Please see the new forum topic I've created, which provides an actual solution to this problem: http://www.mapleprimes.com/forum/importantissuemaplescriptmemoryallocationmacos

MaplePrimes - answers and comments on Question, Mac and Maple Kernel Issue

memory

Out of memory exception

Same problem, and a little more insight...

solution