#199 closed enhancement (fixed)
Weighted events for decays and in analysis
| Reported by: | Juergen Reuter | Owned by: | kilian |
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| Priority: | P2 | Milestone: | |
| Component: | core | Version: | 2.0.0rc2 |
| Severity: | major | Keywords: | events |
| Cc: |
Description
This is mentioned as a TODO in whizard.nw. Should be (re)enabled in WHIZARD 2.
Change History (9)
comment:1 Changed 14 years ago by
| Milestone: | v2.0.0final → v2.0-rc4 |
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| Priority: | P3 → P2 |
comment:2 Changed 14 years ago by
| Owner: | changed from ALL to Juergen Reuter |
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| Priority: | P2 → P1 |
| Status: | new → assigned |
comment:3 Changed 14 years ago by
In W1, event weights are normalized between 0 and 1, in W2 they are multiplied by the corresponding cross section. If there is no good physics or computing reason for using the sample function values, there is no good reason for me not to continue the W1 nomenclature. Please, comment!!!!
comment:4 Changed 14 years ago by
After discussion with CS I will introduce normalized weights between 0 and 1 in W2 as in W1.
comment:5 Changed 14 years ago by
In r2096 I finally activated the weighted events. Now all event formats which write out weights work with weighted events as well (this did not work in W1 !). THe event weights are between 0 and 1, and I abandoned the confusing options of the n_events/n_call interplay in W2. Now n_events is always the number of events that will end up in the event file, both for weighted and unweighted events. For me weighted events seem to be complete, there might be some issues with the analysis when using weighted events, but at least the examples from qedtest.sin are working also with weighted events.
Will try to go to negative weight events as soon as possible.
comment:6 Changed 14 years ago by
| Priority: | P1 → P2 |
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comment:7 Changed 14 years ago by
| Owner: | changed from Juergen Reuter to kilian |
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| Status: | assigned → new |
| Summary: | Event generation for weighted and negative weight events → Weighted events for decays and in analysis |
The negative weight events have been separated into ticket #259. This ticket now includes the correct handling of weighted events for decay cascades as well as weighted events in event analyses for e.g. plotting of distributions like differential cross sections.
comment:8 Changed 14 years ago by
| Resolution: | → fixed |
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| Status: | new → closed |
Thinking over it again, I come to the opinion that decays should be kept unweighted for all modes of event generation. Events weights are used only for the hard interaction, the subsequent decays are selected by rejection. Observables and histograms will come out just right.
This is because decays are treated inclusively when called by the current WHIZARD version. The allowed decay channels are just assumed to saturate the decay width.
It should be possible to treat decays more exclusively, taking into account the full decay width as an independent parameter. But this is the subject of #264.
Will do this, at least for weighted events.