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Re: [igraph] memory usage
From: |
Tamás Nepusz |
Subject: |
Re: [igraph] memory usage |
Date: |
Mon, 30 Jan 2012 13:39:45 +0100 |
Dear Yulia,
> I have recently been searching for information on how much memory is needed
> to store an igraph object.
> During this search I have found two contradictory posts:
> one (from Tamás Nepusz) claiming that igraph allocates 16 bytes per edge + 8
> bytes per vertex,
> and another one (from Gabor Czardi) (it was actually a presentation) saying
> that it allocates twice as much:
> 32 bytes per edge + 16 bytes per vertex.
>
> So I would greatly appreciate if someone could tell me how much memory is
> being used in the current implementation . Or does it somehow depend on the
> OS or the hardware ?
It ultimately depends on the size of the "double" data type in C on your OS or
the hardware. If your "double" is 8 bytes long, then the required memory is
8*4*|E| + 8*2*|V|. I might have been wrong to assume that a "double" takes up
only 4 bytes, so I think that Gabor's figures are correct.
--
Tamas