MadGraph5_aMC@NLO

Output param_card for decays with generate_events

Asked by Nicholas Lange

As is being done in this question (https://answers.launchpad.net/mg5amcnlo/+question/213639), I would like to ensure that I obtain the full set of events in a decay process. To do this I use `launch -i' and run `generate_events' by hand. However, I notice that if I had just run `launch' then MadGraph goes instead for `calculate_decay_widths' which will output an updated param_card.dat with the updated widths. This is not the case for the output when used with `generate_events'.

Is it possible to have generate_events output an updated param_card when used for a decay process? Should I instead just be using calculate_decay_widths and play with the accuracy parameter?

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Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

This is not possible right now, but i think that you should be able to modify the code easily for doing that.

If you modify the files
madevent_interface.py
and add the line
        if self.ninitial == 1:
            self.collect_decay_widths()
at the end of the do_generate_events command (around line 2131)

It might work.

Cheers,

Olivier

On Jun 11, 2014, at 4:21 PM, Nicholas Lange <email address hidden> wrote:

> New question #250105 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/250105
>
> As is being done in this question (https://answers.launchpad.net/mg5amcnlo/+question/213639), I would like to ensure that I obtain the full set of events in a decay process. To do this I use `launch -i' and run `generate_events' by hand. However, I notice that if I had just run `launch' then MadGraph goes instead for `calculate_decay_widths' which will output an updated param_card.dat with the updated widths. This is not the case for the output when used with `generate_events'.
>
> Is it possible to have generate_events output an updated param_card when used for a decay process? Should I instead just be using calculate_decay_widths and play with the accuracy parameter?
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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Nicholas Lange (jimmayl) said : 		#2

Thanks Olivier, I will give that a shot.

Cheers,
-Nick

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Nicholas Lange (jimmayl) said : 		#3

This works great and the param_card.dat is now output alongside the events.
The HTML page however does not put the link in on crossx.html. Is there an easy way to make this happen? It is not crucial but is useful.

Cheers,
-Nick

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Nicholas Lange (jimmayl) said : 		#4

Interestingly enough, I've found this behaviour:

launch -i
generate_events

At this point run_01 goes through, and when completed, crossx.html does not contain a link to param_card.dat for run_01.

quit
launch -i
generate_events

As soon as this process begins, **run_01** gets updated such that its param_card is linked in run_01 of crossx.html
Once this completes, run_02 does not get updated to have the link for its param_card put in.

Weird behaviour. I'm outside of the territory of regular MadGraph usage though I suppose so this is to be expected. If you have any ideas, I'm all ears.

Cheers,
-Nick

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Olivier Mattelaer (olivier-mattelaer) said : 		#5

This probably means that you need to add the following line: (after the previous one)
        self.update_status('generate_events done', level='parton', makehtml=False)

If it doesn't work, you can put the makehtml flag on True.

Cheers,

Olivier

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Nicholas Lange (jimmayl) said : 		#6

This worked. I had tried that I had thought earlier, but I think that I had neglected in putting this within the if statement.

Thanks for your help on this; it is very much appreciated.

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Nicholas Lange (jimmayl) said : 		#7

Thanks Olivier Mattelaer, that solved my question.