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Re: MemopMemmmmo
From: |
John Darrington |
Subject: |
Re: MemopMemmmmo |
Date: |
Sat, 17 Mar 2012 19:06:17 +0000 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Sat, Mar 17, 2012 at 11:13:56AM -0700, Ben Pfaff wrote:
The current default of 64 MB is fairly conservative for modern
systems. I'd be happy to adjust that downward on (presumably
older) systems that have little memory. Perhaps we could use the
gnulib "physmem" module to find that out.
But: Are you sure that the problem is that the default setting is
too high? I would have guessed that the problem is actually one
of two things: either the setting is being raised manually to a
value that is too high for the system, or the categorical code
does not honor the setting regardless of its value. (Without
looking at code, I'd guess that the latter is the case.)
64MB is quite acceptable if it is being called just a few
times, which would be typical of a normal use of a categorical procedure.
However if a continuous variable is unwittingly specified as a categorical
variable, then potentially the system will attempt to allocate 64MB * N
where N is the number of distinct values of that variable. Clearly if N is
very large, that's not going to work.
Consdier the following syntax:
input program.
loop #i = 1 to 250000.
compute A = #i.
compute B = mod(#i, 2).
end case.
end loop.
end file.
end input program.
compute v = rv.uniform (0,1).
EXAMINE
v BY B
/statistics = descriptives
.
This is a perfectly reasonable (albeit uninteresting) use of examine.
However, if the user
inadvertently types "v BY A" instead of "v BY B", then we will dutifully try
to allocate,
64MB * 250000 on the heap.
J'
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- MemopMemmmmo, John Darrington, 2012/03/17
- Re: MemopMemmmmo, Ben Pfaff, 2012/03/17
- Re: MemopMemmmmo,
John Darrington <=
- Re: MemopMemmmmo, Ben Pfaff, 2012/03/17
- Allocating many workspaces., John Darrington, 2012/03/17
- Re: Allocating many workspaces., Ben Pfaff, 2012/03/17
- Re: Allocating many workspaces., John Darrington, 2012/03/18
- Re: Allocating many workspaces., Ben Pfaff, 2012/03/18
- Re: Allocating many workspaces., Ben Pfaff, 2012/03/19