"No more memory available" -- a recurring problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg68356] "No more memory available" -- a recurring problem*From*: "Charlie Brummitt" <cbrummitt at wisc.edu>*Date*: Wed, 2 Aug 2006 05:24:17 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

I keep getting the following error message while running a search of many PDE's: "No more memory available. Mathematica kernel has shut down. Try quitting other applications and then retry." This message is becoming so common that it is crippling my research project, which is to find the simplest PDE with one quadratic nonlinearity that is chaotic. I have Googled and searched the Mathgroup archives for help, and I employed the following fixes: --CODE & SOFTWARE-- 1) Share[] -- does not help because my code rarely has common elements that Share[] could consolidate. 2) I used Module[] and made as many variables local as possible. I eliminated extra variables and functions in addition to adding Clear[] in several places in the code to clear variables that are no longer needed. 3) I streamlined and optimized the code in general, and I made the routines as simple and least data-intensive as possible. 4) I never have any other applications open when running Mathematica. (Unfortunately, closing other applications is the only suggestion that Mathematica provides in the "out of memory" error message.) 5) I should note that I run the latest version of Mathematica (5.2.2.0). --HARDWARE-- 1) I upgraded from a 12" PowerBook to a 15" MacBook Pro. This computer has an 2.16 GHz Intel Core Duo processor. 2) I upgraded the RAM on this new computer from 1 GB to 2 GB. 3) I now have much more free hard drive space (20 GB) in case Mathematica needs to use virtual memory. In addition, this hard drive is 7200 rpm versus the standard 5400 rpm. I have been using functions like MemoryInUse[] and On[MemoryConserve] to monitor the use of memory. I almost always find that I am only using a few megabytes at a time (usually 5-10 MB, sometimes as high as 100 or once 1000 after a large computation). However, despite finding that I usually use only a few megabytes during my computations, I often get the above "out of memory" error message, and I can never figure out why and how much memory was needed in that particular computation. Some questions: 1) How can I tell whether Mathematica is using virtual memory or not? It seems to me that it is not. I have 20 GB of hard drive space free and it never seems to use it. Why should I ever run out of memory if I have 20 GB free in case it needs more memory than my RAM provides? 2) Is there a way to determine how much of my 2 GB of RAM are allocated to Mathematica? Can I increase how much RAM Mathematica can access? Thanks in advance for any help you may be able to provide! I greatly appreciate it. If you need more information on my code or the computations I am doing, I would be happy to provide it. Regards, Charlie

**Follow-Ups**:**Re: "No more memory available" -- a recurring problem***From:*János <janos.lobb@yale.edu>