[Rivet] alpgen+herwig in agile 1.2.2

[Andy Buckley]

Hi Gavin et al. Thanks for the patches... now applied on the AGILe 
trunk. Sorry about the delay!

Since I know virtually nothing about the mechanics of how AlpGen 
interfaces to shower generators (although I'm getting quite familiar 
with HERWIG/JIMMY!), can someone in the know please confirm for me that 
I shouldn't be worried that there is no similar vetoing loop in the 
AlpGenFPythia interface?

Cheers,
Andy


On 28/04/11 17:54, Gavin Hesketh wrote:
> Hello,
> Although I'm a bit worried I might be gaining a reputation as an alpgen
> defender, there is a bug in the new agile which means alpgen+herwig will
> not run correctly.
>
> There are two small tweaks, calling:
>  > FC_HWEVNT.IERROR = -1;
> and
>  > continue; (instead of return)
> when UPVETO fails.
>
> Calling IERROR ensures the event count is correct at the end of the run
> (mostly cosmetic, unless people use this to normalise). Calling continue
> ensures agile does not spit out empty events if upveto fails (which can
> be very often) - this is more serious, and basically makes it unusable
> as (eg) rivet aborts on seeing an empty event.
>
> The two patched files are attached, the diff is below.
>
> cheers,
> Gavin
>
>
>
>
>
>  > diff AlpGenFHerwigJimmy.cc
> build/AGILe-1.2.2/src/AlpGen/AlpGenFHerwigJimmy.cc
> 70d70
> < FC_HWEVNT.IERROR = -1;
> 72c72
> < continue;
> ---
>  > return;
>
>
>
>
>
>
>
>
>  > diff AlpGenFHerwig.cc build/AGILe-1.2.2/src/AlpGen/AlpGenFHerwig.cc
> 57,70c57,65
> <
> < while (true) {
> < FC_HWUINE(); // Initialize event
> < FC_HWEPRO(); // Generate hard subprocess
> < // Call the matching routine
> < int imatch = 0;
> < FC_UPVETO(&imatch);
> < if (imatch != 0) {
> < MSG_DEBUG("Event killed by UPVETO");
> < FC_HWEVNT.IERROR = -1;
> < FC_HWUFNE();
> < continue;
> < }
> < break;
> ---
>  > FC_HWUINE(); // Initialize event
>  > FC_HWEPRO(); // Generate hard subprocess
>  > // Call the matching routine
>  > int imatch = 0;
>  > FC_UPVETO(&imatch);
>  > if (imatch != 0) {
>  > MSG_DEBUG("Event killed by UPVETO");
>  > FC_HWUFNE();
>  > return;
>
> AlpGenFHerwig.cc
>
>
> // -*- C++ -*-
> #include "AGILe/AlpGen/AlpGenFHerwig.hh"
> #include "AGILe/AlpGen/AlpGenWrapper.hh"
> #include "AGILe/FHerwig/FHerwigWrapper65.hh"
> #include "AGILe/Utils.hh"
> #include "HepMC/HEPEVT_Wrapper.h"
>
>
> //-----------------------------------------------------------------------------
> // Implementation file for class : AlpGenFHerwig
> // This is the file-reading interface wrapper only. It contains an instance of
> // FHerwig which does most of the work. This class is only to provide access to
> // the parameter
> // settings.
> //
> // Authors: Jon Butterworth
> //          Andy Buckley
> //-----------------------------------------------------------------------------
>
>
> namespace AGILe {
>
>
>    // Standard constructor
>    AlpGenFHerwig::AlpGenFHerwig() {
>      _myName = "AlpGenHerwig";
>
>      // Set flag to read from LHA event file
>      FC_HWPROC.IPROC = -100;
>      _iprocset = true;
>
>      // Set the ALPGEN filename to "zhjj" by default
>      FC_AHIO.FILENAME[0] = 'z';
>      FC_AHIO.FILENAME[1] = 'h';
>      FC_AHIO.FILENAME[2] = 'j';
>      FC_AHIO.FILENAME[3] = 'j';
>    }
>
>
>    // Set string parameters
>    bool AlpGenFHerwig::setParam(const string&  name, const string&  value) {
>      // Try AlpGen param handling first
>      bool ok = _alpgen.setParam(name, value);
>      if (ok) return SUCCESS;
>      // Fall back to Herwig param handling
>      ok = FHerwig::setParam(name, value);
>      if (ok) return SUCCESS;
>      // Fail
>      MSG_ERROR("AlpGenHerwig doesn't have a parameter called "<<  name);
>      return FAILURE;
>    }
>
>
>    // Call event generation with veto routine for MLM matching
>    void AlpGenFHerwig::makeEvent(HepMC::GenEvent&  evt) {
>      Generator::makeEvent(evt);
>
>      while (true) {
>        FC_HWUINE();  // Initialize event
>        FC_HWEPRO();  // Generate hard subprocess
>        // Call the matching routine
>        int imatch = 0;
>        FC_UPVETO(&imatch);
>        if (imatch != 0) {
> 	MSG_DEBUG("Event killed by UPVETO");
> 	FC_HWEVNT.IERROR = -1;
> 	FC_HWUFNE();
> 	continue;
>        }
>        break;
>      }
>      FC_HWBGEN();  // Generate parton cascade
>      FC_HWDHOB();  // Do heavy quark decays
>      FC_HWCFOR();  // Do cluster formation
>      FC_HWCDEC();  // Do cluster decays
>      FC_HWDHAD();  // Do unstable particle decays
>      FC_HWDHVY();  // Do heavy flavor decays
>      FC_HWMEVT();  // Add soft underlying event
>      FC_HWUFNE();  // Finish event
>      fillEvent(evt);
>      return;
>    }
>
>
> }
>
>
> // Class factory
> extern "C" {
>    AGILe::Generator* create() { return new AGILe::AlpGenFHerwig(); }
>    void destroy(AGILe::Generator* gen) { delete gen; }
> }
>
>
> AlpGenFHerwigJimmy.cc
>
>
> // -*- C++ -*-
> #include "AGILe/AlpGen/AlpGenFHerwigJimmy.hh"
> #include "AGILe/AlpGen/AlpGenWrapper.hh"
> #include "AGILe/FHerwig/FHerwigWrapper65.hh"
> #include "AGILe/FHerwig/JimmyWrapper.hh"
> #include "AGILe/Utils.hh"
> #include "HepMC/HEPEVT_Wrapper.h"
>
>
> //-----------------------------------------------------------------------------
> // Implementation file for class : AlpGenFHerwigJimmy
> // This is the file-reading interface wrapper only. It contains an instance of
> // FHerwigJimmy which does most of the work. This class is only to provide access to
> // the parameter
> // settings.
> //
> // Authors: Jon Butterworth
> //          Andy Buckley
> //-----------------------------------------------------------------------------
>
>
> namespace AGILe {
>
>
>    // Standard constructor
>    AlpGenFHerwigJimmy::AlpGenFHerwigJimmy() {
>      // Set flag to read from LHA event file
>      FC_HWPROC.IPROC = -100;
>      _iprocset = true;
>
>      // Set the ALPGEN filename to "zhjj" by default
>      FC_AHIO.FILENAME[0] = 'z';
>      FC_AHIO.FILENAME[1] = 'h';
>      FC_AHIO.FILENAME[2] = 'j';
>      FC_AHIO.FILENAME[3] = 'j';
>    }
>
>
>    // Set string parameters
>    bool AlpGenFHerwigJimmy::setParam(const string&  name, const string&  value) {
>      // Try AlpGen param handling first
>      bool ok = _alpgen.setParam(name, value);
>      if (ok) return SUCCESS;
>      // Fall back to Herwig+Jimmy param handling
>      ok = FHerwigJimmy::setParam(name, value);
>      if (ok) return SUCCESS;
>      // Fail
>      MSG_ERROR("AlpGenHerwigJimmy doesn't have a parameter called "<<  name);
>      return FAILURE;
>    }
>
>
>    // Call event generation with veto routine for MLM matching
>    void AlpGenFHerwigJimmy::makeEvent(HepMC::GenEvent&  evt) {
>      Generator::makeEvent(evt);
>      while (true) {
>        int counter(0);
>        // Repeat the first stages of event generation until multiple
>        // scattering succeeds (or isn't run at all).
>        while (true) {
> 	
>          FC_HWUINE();  // Initialize event
>          FC_HWEPRO();  // Generate hard subprocess
> 	
>          // Call the AlpGen matching routine
>          int imatch = 0;
>          FC_UPVETO(&imatch);
>          if (imatch != 0) {
>            MSG_DEBUG("Event killed by UPVETO");
> 	  FC_HWEVNT.IERROR = -1;
>            FC_HWUFNE();
>            continue;
>          }
>
>          counter += 1;
>
>          FC_HWBGEN();  // Generate parton cascade
> 	
>          // Call the multiple scattering routine with the abort flag.
>          // If abort is returned with value 1 (true), then abandon the
>          // event. This implementation makes sure that the event generation
>          // continues if multiple scattering is disabled (MSFLAG != 1)
>          int abort(0);
>          if (FC_JMPARM.MSFLAG == 1) FC_HWMSCT(&abort);
>          // If MS is okay or disabled, escape the loop and
>          // continue with the decays and hadronisation.
>          if (abort == 0) {
>            MSG_DEBUG("Num attempts to make MPI = "<<  counter);
>            break;
>          }
> 	
>          // Check for too many attempts to make MPI scatters
>          if (counter>  100) {
>            throw runtime_error("Too many attempts to make MPI in FHerwigJimmy");
>          }
>        }
>        FC_HWDHOB();  // Do heavy quark decays
>        if (_doHadronise) {
>          FC_HWCFOR();  // Do cluster formation
>          FC_HWCDEC();  // Do cluster decays
>          FC_HWDHAD();  // Do unstable particle decays
>          FC_HWDHVY();  // Do heavy flavor decays
>        }
>        FC_HWMEVT();  // Add soft underlying event
>        FC_HWUFNE();  // Finish event
>        if (FC_HWEVNT.IERROR == 0) break;
>      }
>      clearEvent(evt);
>      fillEvent(evt);
>    }
>
>
> }
>
>
> // Class factory
> extern "C" {
>    AGILe::Generator* create() { return new AGILe::AlpGenFHerwigJimmy(); }
>    void destroy(AGILe::Generator* gen) { delete gen; }
> }
>
>
>
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-- 
Dr Andy Buckley
SUPA Advanced Research Fellow
Particle Physics Experiment Group, University of Edinburgh

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