MG5 crashes for many processes, but not for a few

Does it works better if you force the numbering of each processes?

generate p p > n1 c1 $ susystrong @1
add process p p > n1 c1 j $ susystrong @2
add process p p > n1 c1 j j $ susystrong @3
add process p p > n1 n2 $ susystrong @4
add process p p > n1 n2 j $ susystrong @5
add process p p > n1 n2 j j $ susystrong @6
add process p p > c1 n2 $ susystrong @7
add process p p > c1 n2 j $ susystrong @8
add process p p > c1 n2 j j $ susystrong @9
add process p p > c1 c1 $ susystrong @10
add process p p > c1 c1 j $ susystrong @11
add process p p > c1 c1 j j $ susystrong @12

Also what is the logic to generate all of them in one go?
I thought that for CKKW-L with Py8 (and simply for the matching scale) it would be better to have 4 separated computation.

Cheers,

Olivier

Hi Olivier,

Thanks Foy your response, I have tried with the added @1, @2... but got the same result. Do you know of anything else I could try?
We're trying to keep our number of requested samples down, instead of having four different samples for the same mass and lifetime, and thus quadrupling our request.

Thank you,
Marija

Hi,

I fail to reproduce such error (on simpler process, I do not have the ability to compute such process on my laptop). One suggestion would be to do
define X = n1 c1
define Y = n2 c1
generate p p > X Y $ susystrong @1
add process p p > X Y j $ susystrong @2
add process p p > X Y j j $ susystrong @3

Cheers,

Olivier

Hi Olivier,

I'm having the same problem in 2.7.2, though only with relatively small runs. Asking MG to generate 20k events with a proc card like Marija's threw the error, but increasing to 200k events worked fine. I'm not sure if this helps you to debug the issue at all.

Cheers,

-Mike

Hmm, maybe I spoke too soon -- I still see ~10% of my jobs failing, even when running with more events. The only difference between successful and failing jobs is the random seed. So something must be rather unstable.

-Mike

Hi again,

I'm still playing around with this, and maybe this helps more:

From the log file, it looks like we're crashing with this exception in banner.py:

    def modify_init_cross(self, cross):
        """modify the init information with the associate cross-section"""
        assert isinstance(cross, dict)
# assert "all" in cross
        assert "init" in self

        cross = dict(cross)
        for key in cross.keys():
            if isinstance(key, str) and key.isdigit() and int(key) not in cross:
                cross[int(key)] = cross[key]

        all_lines = self["init"].split('\n')
        new_data = []
        new_data.append(all_lines[0])
        for i in range(1, len(all_lines)):
            line = all_lines[i]
            split = line.split()
            if len(split) == 4:
                xsec, xerr, xmax, pid = split
            else:
                new_data += all_lines[i:]
                break
            if int(pid) not in cross:
                raise Exception

I think this is complaining that we can't find a process ID in the init block from the LHE files that are being merged together. I see two partial LHE files in Events/run_01/:

atlas02 | test_guess_008_26 [51]: ls PROC_MSSM_SLHA2_0/Events/run_01/
total 4.1M
-rw-r--r--. 1 nobody users 44K Aug 5 21:51 run_01_tag_1_banner.txt
-rw-r--r--. 1 nobody users 1.1M Aug 5 21:52 partials0.lhe.gz
-rw-r--r--. 1 nobody users 3.0M Aug 5 21:52 partials1.lhe.gz

Looking at the init blocks for those two files:

<init>
2212 2212 6.500000e+03 6.500000e+03 0 0 260000 260000 -4 12
   +7.3565871e-03 +6.7896839e-05 +1.1766687e+01 11
   +4.7601446e-03 +8.1563638e-05 +6.9288533e+00 10
   +1.8776607e+00 +4.9773670e-03 +7.8777596e+00 13
   +2.1637021e-03 +1.3261012e-05 +6.0894384e+00 12
   +5.8831157e-01 +3.3798544e-03 +7.8188791e+00 15
   +1.1177685e+00 +5.1275003e-03 +7.6873225e+00 14
   +1.2539300e-04 +1.6456028e-06 +7.8213219e+00 17
   +1.9666514e-04 +3.5053501e-06 +7.7764568e+00 16
   +6.5569949e-05 +8.3775434e-07 +7.8094409e+00 18
   +2.3384995e+00 +6.0486786e-03 +7.8168534e+00 1
   +4.3344898e-01 +4.0951418e-03 +7.8023543e+00 3
   +1.4318232e+00 +8.0008571e-03 +7.8106911e+00 2
<generator name='MadGraph5_aMC@NLO' version='2.6.7'>please cite 1405.0301 </generator>
</init>

<init>
2212 2212 6.500000e+03 6.500000e+03 0 0 260000 260000 -4 6
   +4.8839995e-03 +4.5076354e-05 +3.0997368e+00 11
   +5.3667600e-03 +9.1957815e-05 +3.1045436e+00 10
   +1.8619488e+00 +4.9357178e-03 +3.1033280e+00 13
   +2.7757069e-03 +1.7011904e-05 +3.1044497e+00 12
   +9.1119429e-02 +8.2545211e-04 +3.0978857e+00 15
   +1.1358744e+00 +5.2105551e-03 +3.1064749e+00 14
<generator name='MadGraph5_aMC@NLO' version='2.6.7'>please cite 1405.0301 </generator>
</init>

so it looks like the process ID's are not unique, and not all process ID's are listed. (e.g. 10 is repeated, and 4 isn't listed anywhere.) I guess the exception arises when the unweighting routine is trying to find a line for a process ID that isn't in the init block.

In my case, I'm trying to run with:

generate p p > n2 x1+ / susystrong @1
add process p p > n2 x1+ j / susystrong @2
add proces...