Pythia 6 aborts after a number of events

Asked by Yehia Abdelaziz

I am trying to generate Bhabha scattering events at the ILC and pythia 6 stops after 39956 events don't know why. I get the following error:

 ********************** PYINIT: initialization completed **********************
******************************************************************************
*** ERROR: Reading events: I/O error, aborting read after 39956 events.
******************************************************************************
| (WHIZARD run continues)
******************************************************************************
*** ERROR: Reading events: I/O error, aborting read after 39956 events.
******************************************************************************
| (WHIZARD run continues)
******************************************************************************
*** ERROR: Reading events: I/O error, aborting read after 39956 events.
******************************************************************************
| (WHIZARD run continues)
******************************************************************************
*** ERROR: Reading events: I/O error, aborting read after 39956 events.
******************************************************************************
| (WHIZARD run continues)
******************************************************************************
*** ERROR: Reading events: I/O error, aborting read after 39956 events.
******************************************************************************
| (WHIZARD run continues)
******************************************************************************
*** ERROR: Reading events: I/O error, aborting read after 39956 events.
******************************************************************************
| (WHIZARD run continues)
******************************************************************************
*** ERROR: Reading events: I/O error, aborting read after 39956 events.
******************************************************************************
| (WHIZARD run continues)
******************************************************************************
*** ERROR: Reading events: I/O error, aborting read after 39956 events.
******************************************************************************
| (WHIZARD run continues)
******************************************************************************
*** ERROR: Reading events: I/O error, aborting read after 39956 events.
******************************************************************************
******************************************************************************
******************************************************************************
*** FATAL ERROR: Too many errors encountered.
******************************************************************************
******************************************************************************

And this is my sindarin script:
sqrts= 500 GeV

?vis_diags=true
process DY = e1, E1 => e1, E1
error_threshold = 1E-8

beams = "e1" , "E1" => circe2 => isr

$circe2_file = "ilc500.circe"
$circe2_design = "ILC"
?circe2_polarized = false

beams_pol_density= @(-1), @(+1)
beams_pol_fraction = 80%, 30%

?ps_fsr_active = true
?hadronization_active = true
$shower_method = "PYTHIA6"
$hadronization_method= "PYTHIA6"

cuts = all M < -10 GeV [incoming e1:E1,e1:E1]
and all Eta < 2.5 [e1:E1]
and all Eta > -2.5 [e1:E1]
and all Pt > 10 GeV [e1:E1]

integrate(DY) {iterations = 10:40000, 6:80000}

$sample = "Drell_Yann_ee_1000000_events_ilc_sqrts_500GeV"
sample_format = lhef

simulate(DY) {n_events = 50000}
show(results)

Question information

Language:
English Edit question
Status:
Solved
For:
WHIZARD Edit question
Assignee:
Juergen Reuter Edit question
Solved by:
Yehia Abdelaziz
Solved:
Last query:
Last reply:
Revision history for this message
Juergen Reuter (j.r.reuter) said :
#1

Dear Yehia,
I just ran your Sindarin file, and I didn't run into that problem. (Sometimes, there are some problems with single events in Pythia6 when it gets stuck in a string fragmentation, but these are usually only single events). The error messages being displayed above show that Whizard tried to read in already generated events from a previous run. In such a case (especially if e.g. some kinematic parameters have changed) it could be that Pythia6 gets stuck. So please use
whizard --rebuild-events
(or even whizard -r to be on the safe side, as this will regenerate also the matrix element code and redo the phase space integration),
or use a fresh workspace folder.
Cheers,
    JRR

Revision history for this message
Yehia Abdelaziz (yehia95) said :
#2

Thank you. This solved my problem.