== Splitting LHEF Event files easily ==

It is sometimes easier to work with large event files (e.g. to use Decay), but its also sometimes easier to work with smaller samples (e.g. for control samples, to reduce the size of PYTHIA files, ...).

If you need to split LHEF files, please use [attachment:split.pl.txt this] PERL script. Download the attachment and then type

{{{
mv split.pl.txt split.pl
}}}

{{{
chmod u+x split.pl
}}}

The syntax is 

=./split.pl perc out1.lhe.gz out2.lhe.gz in.lhe.gz=

where 
{{{
perc
}}} 
is the percentage (between 0 and 100) of events from 
{{{
in.lhe.gz
}}} 
to be saved as 
{{{
out1.lhe.gz
}}}
. The rest is saved in 
{{{
out2.lhe.gz
}}}
. All the information (number of events, unit weight, ...) is updated correctly in the banners and in the event XML blocks.

-- Main.MichelHerquet - 23 Nov 2007