<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>
<body bgcolor="#ffffff" text="#000000">
Hello,<br>
Memory use seems to the topic of the day, as I was just starting to
write this email when I saw that the topic was being discussed on the
developers list:
<a class="moz-txt-link-freetext" href="http://groups.google.com/group/admb-developers/browse_thread/thread/7d687623ab6d9f1b">http://groups.google.com/group/admb-developers/browse_thread/thread/7d687623ab6d9f1b</a><br>
Arni's suggestion of having ADMB tell us how much memory is needed by a
given model might one day solve avoid the problems I'm asking about.<br>
<br>
My first question is about the warning <br>
"Memory allocation error in grad_stack constructor<br>
trying to allocate 2000000000 bytes"<br>
Is this warning (which seem to come from <a
href="http://code.google.com/p/admb-project/source/browse/trunk/src/linad99/gradstak.cpp">this
piece</a> of the source code), just telling me that my 32 bit Windows
XP computer can't handle the amount of memory (slightly below 2GB) that
I'm trying to allocate using the -gbs input? I've got 4GB available,
but maybe 32 bit Windows can't handle more than 2GB for any one
program? A smaller input allows the model to run fine without warning,
but I'd still like to understand the source of the warning.<br>
<br>
My second question is what happens when you enter a value for -cbs or
-gbs that is bigger than 2147483648 (2GB)? It appears that instead of
getting a warning, the model runs, but slower, and using less memory
than what would be associated with a smaller -gbs input. Since the
current method of finding good values for these inputs seems to be
trial and error, perhaps ADMB could help us avoid searching beyond the
maximum for long integers by providing a warning or someone could
clarify that indeed we should not be providing inputs larger than 2^31.<br>
<br>
As I noted <a
href="http://groups.google.com/group/admb-users/browse_thread/thread/8138cac68902c078/a2ea7d9a621d76a1?lnk=gst&q=ian+gbs#a2ea7d9a621d76a1">in
a previous email to this list</a>, there seems to be no problem
allocating lots of memory when we compile models using 64 bit version
of ADMB.<br>
Thanks,<br>
-Ian<br>
<br>
</body>
</html>