MadLoop gfortran Compiling issue

That's an old issue related to some print statement of quadruple precision quantity that make some version of gcc to crash.

Here the best solution is likely to update gcc to a recent version of the code and (maybe or is enough) update
MG5aMC to a more recent version as well.

Note that recent version (2.8+) of MG5aMC requires at least python2.7.

So if you are on a personal laptop, the best is likely to update your OS ( that i would advise for security issue since none of those version are updated anymore in term of security meaning that your system is vulnerable, security patch for python2.6 stops something like 12 years ago).
If you are on cluster, be careful that are likely going to update the os very soon or retired that cluster very soon (again due to security issue) so better to change cluster now (if possible).
But if you can not then read the cluster documentation all clusters have more recent version of python, gcc availble (typically via module)

Cheers,

Olivier

> On 24 Aug 2021, at 10:20, Jihoon Shin <email address hidden> wrote:
>
> New question #698486 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/698486
>
> Hello, I am trying to generate a simple loop induced gg > h process on madgraph.
>
> so I did
>
>> generate g g > h [QCD]
>> output <OUTPUT_DIR>
>> launch
>
> and used only pythia8 and all the card as default except run_card use_syst False because I didn't install LHAPDF.
>
> then I get this error message
>
> Error detected in "generate_events run_01"
> write debug file /home/shin/MG5_aMC_v2_6_5/ggH_loop/run_01_tag_1_debug.log
> If you need help with this issue please contact us on https://answers.launchpad.net/mg5amcnlo
> MadGraph5Error : A compilation Error occurs when trying to compile /home/shin/MG5_aMC_v2_6_5/ggH_loop/SubProcesses/PV0_0_1_gg_h.
> The compilation fails with the following output message:
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c check_sa.f -o check_sa.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c MadLoopParamReader.f -o MadLoopParamReader.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c MadLoopCommons.f -o MadLoopCommons.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -w -fPIC -ffixed-line-length-132 -O3 -c polynomial.f -o polynomial.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c loop_matrix.f -o loop_matrix.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c improve_ps.f -o improve_ps.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c CT_interface.f -o CT_interface.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c loop_num.f -o loop_num.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c helas_calls_ampb_1.f -o helas_calls_ampb_1.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c mp_compute_loop_coefs.f -o mp_compute_loop_coefs.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c mp_helas_calls_ampb_1.f -o mp_helas_calls_ampb_1.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c coef_construction_1.f -o coef_construction_1.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c loop_CT_calls_1.f -o loop_CT_calls_1.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c mp_coef_construction_1.f -o mp_coef_construction_1.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c TIR_interface.f -o TIR_interface.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c compute_color_flows.f -o compute_color_flows.o -I /home/shin/MG5_aMC_v2_6_5/HEPTools/include
> gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -o check check_sa.o MadLoopParamReader.o MadLoopCommons.o polynomial.o loop_matrix.o improve_ps.o CT_interface.o loop_num.o helas_calls_ampb_1.o mp_compute_loop_coefs.o mp_helas_calls_ampb_1.o coef_construction_1.o loop_CT_calls_1.o mp_coef_construction_1.o TIR_interface.o compute_color_flows.o -L../../lib/ -ldhelas -lmodel -L../../lib/ -lcts -liregi -L/home/shin/MG5_aMC_v2_6_5/HEPTools/lib/ -lninja -L/home/shin/MG5_aMC_v2_6_5/HEPTools/lib/ -lavh_olo -lstdc++
> /home/shin/MG5_aMC_v2_6_5/HEPTools/lib//libavh_olo.a(avh_olo.o): In function `__avh_olo_qp_print_MOD_printr':
> avh_olo.f90:(.text+0x8a312): undefined reference to `_gfortran_transfer_real128_write'
> collect2: error: ld returned 1 exit status
> make: *** [check] Error 1
>
> Please try to fix this compilations issue and retry.
> Help might be found at https://answers.launchpad.net/mg5amcnlo.
> If you think that this is a bug, you can report this at https://bugs.launchpad.net/mg5amcnlo
>
> my gcc version is 4.8.2. and python 2.6.6
>
> I did try to recompile /vendor/CutTools because I saw a similar issue and that was a given solution, but that did not solve my case.
>
> Any help will be greatly appreciated
>
> Thank you
>
>
>
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