# granularity in gridpack event generation

Hi,

I am confused about the default value for the granularity when generating events with a gridpack. If I understand https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/IntroGrid correctly, the default value should be $\sqrt{N}$. However, the actual default seems to be 1: when I execute ./run.sh 10000 37, the first output line is

Now generating 10000 events with random seed 37 and granularity 1

Is this expected? Should I change the granularity to $\sqrt{N}$ or leave it as it is?

Cheers,

Eric

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Olivier Mattelaer
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2019-10-16
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2019-10-16
2019-10-16
 Olivier Mattelaer (olivier-mattelaer) said on 2019-10-16: #1

This change was a request of CMS.

setting it to one has advantages concerning statistical fluctuation of the final sample. Even if indeed the optimal value should be $\sqrt{N}$ in term of efficiency.

Cheers,

Olivier

 Eric (e-r-i-c) said on 2019-10-16: #2

Thanks Olivier Mattelaer, that solved my question.