lp:~maddevelopers/mg5amcnlo/MadSpin

Usage
******

the way to use MadSpin is to lauch either the madevent interface
or the aMCatNLO interface and to type decay_events.

The user is asked to provide
 - the path to the input lhe file,
 - the set of particles which should be decayed
   and enter the corresponding decay channel,
 - the maximum weight (if unknown, it is calculated)
 - the overal branching fraction

Output file
***********

If the input file is of the type

Events/run_01/unweighted_events.lhe.gz

then the output file is

Events/run_01/unweighted_events_decayed.lhe.gz

The banner of this new event file contains
extra following lines of the type

<DECAY>
# p p > t t~ H , ( t > b w+ , w+ > mu+ vm ) , ( t~ > b~ w- , w- > mu- vm~ ) , h > b b~
# branching fraction: 1.0
# estimate of the maximum weight: 3.5928221952e-10
</DECAY>

 - "branching fraction" is the real number by which the weight
    of each event is rescaled (provided by the user)
 - "estimate of the maximum weight" is the max. weight that has been
   used for the unweighting procedure (keep record of this number
   in case the user wants to decay another set of tt~H events and skip
   the evaluation of the max. weight)

Limitations
***********

There are currently several limitations, which are brought to the attention
of the user when decay_events is launched:

MGME5>decay_events
INFO: This functionality allows for the decay of resonances
INFO: in a .lhe file, keeping track of the spin correlation effets.
INFO: BE AWARE OF THE CURRENT LIMITATIONS:
INFO: (1) exclusive decay channel only,
INFO: YOU CANNOT USE MULTI-PARTICLE TAG
INFO: (2) the overall branching fraction must
INFO: specified by the user (otherwise the
INFO: is not rescaled)
INFO: (3) only decay channels with splitting of the type
INFO: A -> B(stable) + C(unstable)
INFO: have been tested so far
INFO: (4) when entering the decay chain structure,
INFO: please note that the reading module is
INFO: CASE SENSITIVE

tests
*****

I added a directory madspin inside tests/unit_tests
There are currently two tests:

 - a test to check that the banner is read correctly,
 - a test to check that the matrix elements are correctly evaluated.

Validations
***********

decay_events seems to work fine for single-top, tt~ and tt~h events.
(I plan to check other processes as well)
I had no failure with the unit tests.

I also lauched the acceptance tests, but I had the following errors
BOTH in the MadSpin version and in the primary aMCatNLO version:

F..........................E.E....cp: /Users/partois/mg5_developments/aMCatNLO/Template/Source/make_opts: No such file or directory
F
======================================================================
ERROR: test_creating_matched_plot (tests.acceptance_tests.test_cmd_madevent.TestMECmdShell)
test that the creation of matched plot works
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/partois/mg5_developments/aMCatNLO/tests/acceptance_tests/test_cmd_madevent.py", line 115, in test_creating_matched_plot
    self.generate('p p > W+ j', 'sm')
  File "/Users/partois/mg5_developments/aMCatNLO/tests/acceptance_tests/test_cmd_madevent.py", line 70, in generate
    raise Exception, 'root is require for this test'
Exception: root is require for this test

======================================================================
ERROR: test_width_computation (tests.acceptance_tests.test_cmd_madevent.TestMECmdShell)
test the param_card created is correct
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/partois/mg5_developments/aMCatNLO/tests/acceptance_tests/test_cmd_madevent.py", line 91, in test_width_computation
    self.generate(['Z > l+ l-','Z > j j'], 'sm')
  File "/Users/partois/mg5_developments/aMCatNLO/tests/acceptance_tests/test_cmd_madevent.py", line 70, in generate
    raise Exception, 'root is require for this test'
Exception: root is require for this test

======================================================================
FAIL: test_config (tests.acceptance_tests.test_cmd.TestCmdShell1)
check that configuration file is at default value
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/partois/mg5_developments/aMCatNLO/tests/acceptance_tests/test_cmd.py", line 146, in test_config
    self.assertEqual(config, expected)
AssertionError: {'web_browser': None, 'text_editor': None, 'cluster_temp_path': None, 'lhapdf': [truncated]... != {'web_browser': None, 'text_editor': None, 'cluster_temp_path': None, 'lhapdf': [truncated]...
  {'auto_update': 7,
   'automatic_html_opening': True,
   'cluster_queue': None,
   'cluster_temp_path': None,
   'cluster_type': 'condor',
   'complex_mass_scheme': False,
   'eps_viewer': None,
   'fastjet': 'fastjet-config',
+ 'fks_mode': 'real',
   'fortran_compiler': None,
   'gauge': 'unitary',
   'group_subprocesses': 'Auto',
   'ignore_six_quark_processes': False,
   'lhapdf': 'lhapdf-config',
- 'loop_optimized_output': True,
? ^^^

+ 'loop_optimized_output': False,
? ^^^^

   'nb_core': None,
   'run_mode': 2,
   'text_editor': None,
   'timeout': 60,
   'web_browser': None}

======================================================================
FAIL: test_all (tests.acceptance_tests.test_model_equivalence.TestModelCreation)
test all the files
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/partois/mg5_developments/aMCatNLO/tests/acceptance_tests/test_model_equivalence.py", line 301, in test_all
    self.check_compilation()
  File "/Users/partois/mg5_developments/aMCatNLO/tests/acceptance_tests/test_model_equivalence.py", line 329, in check_compilation
    self.assertTrue(os.path.exists(self.give_pos('testprog')))
AssertionError: False is not true

----------------------------------------------------------------------
Ran 35 tests in 298.052s

FAILED (failures=2, errors=2)