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Feature #20063

Random numbers in MixFilter detail

Added by Andrei Gaponenko almost 3 years ago. Updated about 2 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Kyle Knoepfel
Category:
Infrastructure
Target version:
3.02.00
Start date:
05/30/2018
Due date:
% Done:

100%

Estimated time:
Spent time:
3.00 h
Scope:
Internal
Experiment:
Mu2e
SSI Package:
art
Duration:

Description

Hello,

Users can call initialize a random engine in a module constructor with
the createEngine(seed) call. To achieve this in mixing code one has to
take a more contorted way, and put in the MixFilter detail class
constructor something like

   art::RandomNumberGenerator::base_engine_t& engine = art::ServiceHandle<art::RandomNumberGenerator>()->getEngine();
   int dummy(0);
   engine.setSeed( art::ServiceHandle<SeedService>()->getSeed(), dummy );

It would be nice to streamline the interface for MixFilter users.

Andrei

History

#1 Updated by Kyle Knoepfel almost 3 years ago

  • Description updated (diff)

#2 Updated by Kyle Knoepfel almost 3 years ago

  • Status changed from New to Accepted

This sounds like a reasonable proposal.

#3 Updated by Kyle Knoepfel almost 3 years ago

  • Target version set to Vega

#4 Updated by Kyle Knoepfel almost 3 years ago

  • Category set to Infrastructure
  • Status changed from Accepted to Resolved
  • Assignee set to Kyle Knoepfel
  • % Done changed from 0 to 100
  • SSI Package art added

This feature has been implemented with art:652b484. The createEngine interface has been added to the MixHelper class. Note that under some circumstances, the MixHelper already requires the use of a random-number engine for sampling entries in secondary files. In such case, calling createEngine may return an engine that has already been created. This will not create any breaking changes since users have had the same behavior by calling getEngine.

An example:

MixFilterDetail::MixFilterDetail(fhicl::ParameterSet const& pset,
                                 art::MixHelper& helper)
  // initializers
{
  auto& engine1 = helper.createEngine(124);                   // May return already created engine
  auto& engine2 = helper.createEngine(125, "HepJamesRandom"); // May return already created engine
  auto& engine3 = helper.createEngine(126, "HepJamesRandom", "second_engine"); // new engine

  // If an empty engine label has been specified, but with a different 
  // engine type other than HepJamesRandom, an exception will be thrown
  // if a read mode was chosen that requires sampling.
  auto& engine4 = helper.createEngine(127, "MTwistEngine");   // May throw.
}

#5 Updated by Kyle Knoepfel over 2 years ago

  • Target version changed from Vega to 3.01.00

#6 Updated by Kyle Knoepfel over 2 years ago

  • Target version changed from 3.01.00 to 3.02.00

#7 Updated by Kyle Knoepfel about 2 years ago

  • Status changed from Resolved to Closed

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