已安装 Python 2.7 和 Python 3.7。 如何将 MadGraph 与 Python 2.7 一起使用？

Question

I am working with a simulation software MadGraph that is written in python. MadGraph is only compatible with python 2.7. My MadGraph is installed in /mnt/c/1 folder with Python 3.7.4 as I can see when I type ls in the /mnt/c/1 directory. But when I type in the /mnt/c/1 directory python --version I get python 2.7.15+. In /mnt/c/1MG5_aMC_v2_6_6 directory I type ls and I can't find python. When I type which python in the same directory I get /usr/bin/python. When I type ls bin I just get MadGraph and no python.

My question is how can I have python 2.7 working with MadGraph. I can work with MadGraph up to a certain point. When I want to type in a certain command in MadGraph I get this error:

Total: 4 processes with 4 diagrams
MG5_aMC>display diagrams
Drawing Process: u u~ > z > mu+ mu- WEIGHTED<=4 @1
Wrote file /tmp/diagrams_1_uux_z_mupmum.eps
open /tmp/diagrams_1_uux_z_mupmum.eps
Drawing Process: c c~ > z > mu+ mu- WEIGHTED<=4 @1
Wrote file /tmp/diagrams_1_ccx_z_mupmum.eps
open /tmp/diagrams_1_ccx_z_mupmum.eps
Drawing Process: d d~ > z > mu+ mu- WEIGHTED<=4 @1
Unhandled exception in thread started by <function call at 
0x7fbbb476bc08>Wrote file /tmp/diagrams_1_ddx_z_mupmum.eps

Traceback (most recent call last):
open /tmp/diagrams_1_ddx_z_mupmum.eps
File "/usr/lib/python2.7/subprocess.py", line 172, in call
Drawing Process: s s~ > z > mu+ mu- WEIGHTED<=4 @1
Unhandled exception in thread started by <function call at 0x7fbbb476bc08>
Traceback (most recent call last):
File "/usr/lib/python2.7/subprocess.py", line 172, in call
return Popen(*popenargs, **kwargs).wait()
return Popen(*popenargs, **kwargs).wait()
File "/usr/lib/python2.7/subprocess.py", line 394, in __init__
File "/usr/lib/python2.7/subprocess.py", line 394, in __init__
    errread, errwrite)
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1047, in _execute_child
File "/usr/lib/python2.7/subprocess.py", line 1047, in _execute_child
Wrote file /tmp/diagrams_1_ssx_z_mupmum.eps
open /tmp/diagrams_1_ssx_z_mupmum.eps
raise child_exception
time to draw 0.063835144043
raise child_exception
OSErrorOSError: [Errno 2] No such file or directory: [Errno 2] No such 
file or directory
MG5_aMC>
Unhandled exception in thread started by <function call at 0x7fbbb476bc08>
Traceback (most recent call last):
File "/usr/lib/python2.7/subprocess.py", line 172, in call
return Popen(*popenargs, **kwargs).wait()
File "/usr/lib/python2.7/subprocess.py", line 394, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1047, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
Unhandled exception in thread started by <function call at 0x7fbbb476bc08>
Traceback (most recent call last):
File "/usr/lib/python2.7/subprocess.py", line 172, in call
return Popen(*popenargs, **kwargs).wait()
File "/usr/lib/python2.7/subprocess.py", line 394, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1047, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory

I don't understand why I get this OS error for this certain command (of displaying the diagrams of the process that was simulated/generated). I can simulate the process fine but I can't display the diagrams. I end up with the error above and it gets stuck and I have to ctrl+c. I am wondering if it is because of the different python versions I have installed. I am just trying to understand this error written in python and how I can fix it. I would really appreciate some help. thanks!

Answer 1

MisterMiyagi is correct - the traceback shows that MadGraph is using Python 2.7.

However, when you type a "command", MadGraph tries to Popen() some other script or executable. You're getting an "errno 2" exception: whatever script or executable MadGraph is trying to open, it can't find it in your current PATH .

SUGGESTIONS:

1. Try strace to determine exactly what file Popen is trying to find.

2. Modify your PATH to include the directory this file is located in.

Please post back what you find.