Problem in h > b b~ g

Asked by teddym on 2018-11-02

Hi:
    We are trying to generate following process:

generate h > b b~ g [QCD]

However, there are some problems:
1. after launch, the Shower option and Fix order option are shown in red (in other case, they will be light green) and when I change them, it will also say ``not installed''

2. MG5 return following error, and no events generated and no width got:
xxxxxx/P0_h_bbxg/ajob1 1 all 1 2 launch ends with non zero status: 139. Stop all computation

What is the problem in this case? How should I fix that? Thanks so much

Best
ycwu

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
Rikkert Frederix Edit question
Last query:
2018-11-08
Last reply:
2018-11-08
Rikkert Frederix (frederix) said : #1

Dear ycwu,

Only fixed-order NLO (i.e., without (matching to) the parton shower) is possible for decay processes. Furthermore, a gluon is not a well-defined object at NLO, hence, you'll have to do

generate h > b b~ j [QCD]

where 'j' is defined as all the massless quarks and the gluon.

Best regards,
Rikkert

Note that I just notice a bug with the question in our development version, where it was setting as default fix order on False:

The following patch fix that issue:

=== modified file 'madgraph/interface/amcatnlo_run_interface.py'
--- madgraph/interface/amcatnlo_run_interface.py 2018-08-27 14:51:23 +0000
+++ madgraph/interface/amcatnlo_run_interface.py 2018-11-02 20:17:54 +0000
@@ -1053,7 +1053,10 @@

         if self.last_mode in ['LO', 'NLO']:
             self.switch['fixed_order'] = 'ON'
- self.switch['fixed_order'] = 'OFF'
+ if self.proc_characteristics['ninitial'] == 1:
+ self.switch['fixed_order'] = 'ON'
+ else:
+ self.switch['fixed_order'] = 'OFF'

     def color_for_fixed_order(self, switch_value):

@@ -1158,6 +1161,10 @@
         if self.last_mode in ['LO', 'NLO', 'noshower', 'noshowerLO']:
             self.switch['shower'] = 'OFF'
             return
+
+ if self.proc_characteristics['ninitial'] == 1:
+ self.switch['shower'] = 'OFF'
+ return

         if os.path.exists(pjoin(self.me_dir, 'Cards', 'shower_card.dat')):
             self.switch['shower'] = self.run_card['parton_shower']

Cheers,

Olivier

Rikkert Frederix (frederix) said : #3

Thanks Olivier.

Cheers,
Rik

teddym (niepanchongsheng) said : #4

Hi Rik:
    After regenerating the process with:
generate h > b b~ j [QCD]

the MG5 still produce the same error .
Am I doing something wrong?

Best
ycwu

Rikkert Frederix (frederix) said : #5

Dear ycwu,

Are you including matching to the parton shower or are you running at fixed order? As pointed out in my first message, only the latter is possible with decay processes.

Best,
Rikkert

teddym (niepanchongsheng) said : #6

Dear Rikkert:
    I was running at Fixed Order. But it still throw error:

xxxxx/xxxxx/ajob1 1 all 1 2 launch ends with non zero status: 139. Stop all computation

Thanks!

Best
ycwu

Rikkert Frederix (frederix) said : #7

Dear ycwu,

I just tried myself and the code runs without problems for this process. I'm using the latest public version.
Do the log files in the <YourProcess>/SubProcesses/P*/all_G*/ directories give you any hint on the problem?

Best,
Rikkert

teddym (niepanchongsheng) said : #8

Dear Rikkert:
    I saw in SubProcesses/P0_h_bbxg/all_G1_*/log.txt following errors (lots of such errors, so I just pick two lines):

ERROR in OneLOop dilog2_r: j1, j2, r1-r2 -2 0, .00000000000E+00, returning 0
ERROR in OneLOop log1_r: rr,jj = .1000000000000000E+01 -2 , putting jj to 0

And in all_G1_1/log.txt, there is Segmentation fault:

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0 0x7F1E6E706697
#1 0x7F1E6E706CDE
#2 0x7F1E60E012EF
#3 0x7F1E60F21774
#4 0x7F1E6E7DAAC3
#5 0x7F1E6E7D1DF2
#6 0x455ABA in void fastjet::ClusterSequenceArea::initialize_and_run_cswa<fastjet::PseudoJet>(std::vector<fastjet::PseudoJet, std::allocator<fastjet::PseudoJet> > cons t&, fastjet::JetDefinition const&)
#7 0x4819B7 in std::vector<int, std::allocator<int> >::_M_insert_aux(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int const&)
#8 0x47B191 in std::vector<int, std::allocator<int> >::_M_insert_aux(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int const&)
#9 0x47CDC6 in std::vector<int, std::allocator<int> >::_M_insert_aux(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int const&)
#10 0x7F1E60DED444
#11 0x409ED7
#12 0xFFFFFFFFFFFFFFFF

I have no idea about this. I'm using the MG5-2.6.3.2

Thanks!
ycwu

Rikkert Frederix (frederix) said : #9

Dear ycwu,

Hmm... I've not seen this error before and I'm not sure what's going on. It looks a bit like a compiler issue. Maybe some incompatibility in the compilation of fastjet (which is C++) and MG5_aMC (which is in Fortran). I'm not sure though. Olivier do you have a clue?

Best,
Rikkert

Hi,

Did you link MG5aMC to your own version of fastjet?
Or did you use the built-in one shipped with the code (fjcore)

Cheers,

Olivier

teddym (niepanchongsheng) said : #11

Hi Olivier:
    I linked MG5aMC to my own fastjet, the version is 3.3.0.

Best
ycwu

Can you try without that link?
For what I see in your log, this is a crash on fastjet, so I'm not able to comment more.
Since it works for me/Rikkert. It is likely that such issue is not present on the fjcore version of fastjet.

Cheers,

Olivier

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