MadGraph5_aMC@NLO

Numerical precision of LO processes in MG5_2.3.3

Asked by Felix

Hi Madgraph-Team,

I do have a question about the numerical precision of LO matrix elements in MG. With MG5, version 2.3.3., I`m looking at pure SM processes with heavy quarks (b,t) and a number of gluons (4,5,6,7 legs), using the cpp standalone, evaluated at one specific phase-space point.

- To which numerical precision are the values correct?
- Is there a way to increase the precision, i.e., to switch on a high-precision calculation?

Thanks for looking into this,
Felix

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

All the computation uses “double”.
Now this does not guarantee that the precision is that high due to possible numerical cancelation.

> - Is there a way to increase the precision, i.e., to switch on a high-precision calculation?

We do not have such options.

Cheers,

Olivier

> On Mar 22, 2016, at 15:52, Felix <email address hidden> wrote:
>
> New question #289097 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/289097
>
> Hi Madgraph-Team,
>
> I do have a question about the numerical precision of LO matrix elements in MG. With MG5, version 2.3.3., I`m looking at pure SM processes with heavy quarks (b,t) and a number of gluons (4,5,6,7 legs), using the cpp standalone, evaluated at one specific phase-space point.
>
> - To which numerical precision are the values correct?
> - Is there a way to increase the precision, i.e., to switch on a high-precision calculation?
>
> Thanks for looking into this,
> Felix
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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