The following floating-point exceptions are signalling: IEEE_DIVIDE_BY_ZERO

I put more complete output below, in case it is needed. Thanks!

set ebeam2 1e9
INFO: modify parameter ebeam2 of the run_card.dat to 1000000000.0
Do you want to edit a card (press enter to bypass editing)?
/------------------------------------------------------------\
| 1. param : param_card.dat |
| 2. run : run_card.dat |
\------------------------------------------------------------/
 you can also
   - enter the path to a valid card or banner.
   - use the 'set' command to modify a parameter directly.
     The set option works only for param_card and run_card.
     Type 'help set' for more information on this command.
   - call an external program (ASperGE/MadWidth/...).
     Type 'help' for the list of available command
 [0, done, 1, param, 2, run, enter path]
found line : launch
This answer is not valid for current question. Keep it for next question and use here default: 0
WARNING: Particle 15 will use a fake width ( 1.777e-06 instead of 2.27e-12 ).
Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
INFO: Update the dependent parameter of the param_card.dat
Generating 100 events with run name run_09
survey run_09
INFO: compile directory
write compile file for card: /Users/beizhou/Dropbox/1acdm/1work_ptnl/20180725_Tridents_HE/MadGraph_work/pveTOje_smfull_pjfull1/Cards/param_card.dat
run_card missed argument polbeam1. Takes default: 0.0
run_card missed argument polbeam2. Takes default: 0.0
run_card missed argument nb_proton1. Takes default: 1
run_card missed argument nb_proton2. Takes default: 1
run_card missed argument nb_neutron1. Takes default: 0
run_card missed argument nb_neutron2. Takes default: 0
run_card missed argument mass_ion1. Takes default: -1.0
run_card missed argument mass_ion2. Takes default: -1.0
run_card missed argument highestmult. Takes default: 1
run_card missed argument ktscheme. Takes default: 1
run_card missed argument pdfwgt. Takes default: True
run_card missed argument gridrun. Takes default: False
run_card missed argument fixed_couplings. Takes default: True
run_card missed argument mc_grouped_subproc. Takes default: True
run_card missed argument xmtcentral. Takes default: 0.0
run_card missed argument d. Takes default: 1.0
run_card missed argument issgridfile. Takes default:
run_card missed argument small_width_treatment. Takes default: 1e-06
compile Source Directory
Compiling the bias module 'dummy'
Using random number seed offset = 93
INFO: Running Survey
Creating Jobs
Working on SubProcesses
INFO: P1_qvl_qem
INFO: P1_qvl_cem
INFO: P1_qvl_tem
INFO: P1_qvl_bxem
INFO: P1_bvl_qem
INFO: P1_bvl_cem
INFO: P1_bvl_tem
INFO: P1_cxvl_qem
INFO: P1_cxvl_bxem
INFO: P1_txvl_qem
INFO: P1_txvl_bxem
Note: The following floating-point exceptions are signalling: IEEE_DIVIDE_BY_ZERO
INFO: Idle: 1, Running: 0, Completed: 10 [ current time: 16h08 ]
INFO: Idle: 0, Running: 1, Completed: 10 [ current time: 16h08 ]
Note: The following floating-point exceptions are signalling: IEEE_DIVIDE_BY_ZERO
INFO: Idle: 0, Running: 0, Completed: 11 [ 0.75s ]
INFO: End survey
refine 100
Creating Jobs
INFO: Refine results to 100
INFO: Generating 100.0 unweigthed events.
INFO: Effective Luminosity 0.0331732009432 pb^-1
DEBUG: channel G1 is at 0.0253 (1.31119371317) (2053.1 pb)
INFO: need to improve 1 channels
DEBUG: G1 : need 68.1078988565 event. Need 1 split job of 5000 points
Current estimate of cross-section: 3617.3777805 +- 102.583098506
    P1_qvl_qem
    P1_qvl_cem
    P1_qvl_tem
    P1_qvl_bxem
    P1_bvl_qem
    P1_bvl_cem
    P1_bvl_tem
    P1_cxvl_qem
    P1_cxvl_bxem
    P1_txvl_qem
    P1_txvl_bxem
INFO: Idle: 0, Running: 1, Completed: 0 [ current time: 16h08 ]
INFO: Idle: 0, Running: 0, Completed: 1 [ 1.3s ]
INFO: Combining runs
INFO: finish refine
refine 100
Creating Jobs
INFO: Refine results to 100
INFO: Generating 100.0 unweigthed events.
INFO: Effective Luminosity 0.0336456983095 pb^-1
INFO: need to improve 0 channels
Current estimate of cross-section: 3566.5777805 +- 48.9332123115
    P1_qvl_qem
    P1_qvl_cem
    P1_qvl_tem
    P1_qvl_bxem
    P1_bvl_qem
    P1_bvl_cem
    P1_bvl_tem
    P1_cxvl_qem
    P1_cxvl_bxem
    P1_txvl_qem
    P1_txvl_bxem
INFO: Idle: 0, Running: 0, Completed: 0 [ current time: 16h08 ]
INFO: Combining runs
INFO: finish refine
INFO: Combining Events
DEBUG: write 100 event (efficiency 15 %, truncation 0 %) after 1 iteration(s)
  === Results Summary for run: run_09 tag: tag_1 ===

     Cross-section : 3567 +- 48.93 pb
     Nb of events : 100

INFO: can not run systematics with lhapdf 5
store_events
INFO: Storing parton level results
INFO: End Parton
reweight -from_cards
decay_events -from_cards
INFO: storing files of previous run
INFO: Done
quit

Another question is, if I want do calculate the 5 or 6 flavor case, can I just redefine the p and j like the command in the initial question and then do the same thing as default p and j?
(i.e.
define p g u c d s b t u~ c~ d~ s~ b~ t~
define j g u c d s b t u~ c~ d~ s~ b~ t~
)

Thanks!

Hi,

In general, the DGLAP equation used for the evolution of the PDF are for massless quark.
(they might be exception for some dedicated PDF/PDF implementation).

Now some arguee that even if this is technically incorrect, it actually helps for the parton-showerhadronization phase where all quarks and gluon are set massive.
In that case, you allow yourself some inconsistencies and you can indeed redefine by hand the proton definition.

For 5 flavour computation, we have actually automated all the modification that need to be done to have the computation meaningfull. For using such automation, you only have to import a model where the mass of the five lightest quark is set to 0 (at the model level!).

For 6 flavour computation, we do not have such automation, so in this case, you have
1) to pass a model where all 6 mass are zero at the model level
2) redefine the "p" and "j" muliti-variable
3) change your PDF in the run_card to use one which has a top component
4) change the parameter of the run_card "asrwgtflavor" to 6
5) change the parameter of the run_card "maxjetflavor" to 6

Concerning your crash, the problem might be a boost issue since you are asking to write the events in the rest-frame of the proton, I found quite complex to write the momentum of a b quark in that frame in a consistent way since the mass of the b quark is larger than the mass of the proton.
I did not test, but setting those mass to zero might solve your problem (and will make the computation more meaningfull).

Cheers,

Olivier

> On 7 Mar 2019, at 02:23, Qiji Xin <email address hidden> wrote:
>
> Question #679008 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/679008
>
> Qiji Xin gave more information on the question:
> Another question is, if I want do calculate the 5 or 6 flavor case, can I just redefine the p and j like the command in the initial question and then do the same thing as default p and j?
> (i.e.
> define p g u c d s b t u~ c~ d~ s~ b~ t~
> define j g u c d s b t u~ c~ d~ s~ b~ t~
> )
>
> Thanks!
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Olivier,

Thanks so much for your reply!
Some quick follow-up question.

1)
You mentioned a few times that set the masses of the partons to be zero at model level.
Do you mean I should use, for example, "import model sm" or "import model sm-lepton_masses" that doesn't have quark masses, instead of using "import model sm-full" which has all the masses?

2)
However, using the "sm-full" with 5-flavor or 6-flavor cases, I still went through the calculations and got the cross sections, with or without the warnings mentioned above. I think, since you mentioned a few times that setting the parton masses to be zero will make the computation more meaningful, my such calculation is less meaningful or less trustworthy?

3)
> Concerning your crash, the problem might be a boost issue since you are asking to write the events in the rest-frame of the proton, I found quite complex to write the momentum of a b quark in that frame in a consistent way since the mass of the b quark is larger than the mass of the proton.
> I did not test, but setting those mass to zero might solve your problem (and will make the computation more meaningful).

So if the warning is really due to the boost, the cross section, which is Lorentz invariant, it calculated should not be affected?

I did another test, I remove the top quark component from my proton, i.e. define p = g, u, d, s, c, b, u~, d~, s~, c~, b~. And the other things I use are same as above (e.g. sm-full, etc.). After removing the top quark I don't get he warning at now. Any implication on the possible interpretation of the warning?

4)
Following 3), I got totally the same cross section after removing the top from proton. Does it mean that the PDF doesn't have the top information? (I am using the default PDF of MadGraph run_Card.dat.)

Thanks!

Hi Olivier,

Thanks very much for your reply!

Another follow-up question, regarding what you said about the restrict_XXXX and important sm_XXXX.

If I wanna do this based on the sm-full, what should I do?

Under models/sm/ I see, for exmaple, restrict_lepton_masses.dat which corresponds to sm-lepton_masses and restrict_default.dat which corresponds to sm I think.
But why I don't see restrict_full that might be supposed to correspond to sm-full?
Or the files for sm-full is under other directories?

Thanks!

import model sm
correspond to restrict_default.dat

import model sm-full
correspond to the original UFO file without any additional restriction.

Cheers,

Olivier

> On 8 Mar 2019, at 02:13, Qiji Xin <email address hidden> wrote:
>
> Question #679008 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/679008
>
> Status: Answered => Open
>
> Qiji Xin is still having a problem:
> Hi Olivier,
>
> Thanks very much for your reply!
>
> Another follow-up question, regarding what you said about the
> restrict_XXXX and important sm_XXXX.
>
> If I wanna do this based on the sm-full, what should I do?
>
> Under models/sm/ I see, for exmaple, restrict_lepton_masses.dat which corresponds to sm-lepton_masses and restrict_default.dat which corresponds to sm I think.
> But why I don't see restrict_full that might be supposed to correspond to sm-full?
> Or the files for sm-full is under other directories?
>
> Thanks!
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thanks Olivier Mattelaer, that solved my question.