[molpro-user] direct-MC-SCF is filling harddisk
knizia at theochem.uni-stuttgart.de
Wed Jun 16 07:19:31 BST 2010
On Tuesday 15 June 2010 12:41, andreas.b.fuchs at basf.com wrote:
> Okay, lsof showed me some big files with the status 'deleted'. I assume
> that these are some temporary files which are responsible for the filling
> of my disk.
> Has anyone an idea what is written to these files and how I can prevent
> molpro from writing to these files?
There are some very small items which, as far as I know, are always written to
disk (like orbital matrices, one-electron operators). There are also some
items like the K^ij_ab Exchange- and J^ij_ab Coulomb matrices that can get
semi-large in certain cases, and which I think are also always written to
disk when required, but I am not sure about that.
A correlation method being "direct" mainly means that the full 4 index AO
integrals are not written to disk; these are the quantities that easily take
up TBs and typically are the main disk space bottleneck. The other
quantities, like the K^ij_ab and J^ij_ab integrals, are usually smaller than
these by at least two orders of magnitude (but if using very small basis
sets, the relative size ratio can become worse).
So, in short: "direct" does not mean that nothing is written to disk, only
that much less is written to disk; and there are some special cases in which
the written data is still not entirely negligible compared with the
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