CODEWITHSUNDEEP
pythonpython-3.xattributeerror
Izzy
Izzy

Reputation: 189

AttributeError: dlsym(RTLD_DEFAULT, run): symbol not found - meaning

I am attempting to use the PyMultinest package. The full error text I am encountering is AttributeError:dlsym(RTLD_DEFAULT, run): symbol not found in the __getitem__() function in ctypes/__init__.py. I'll include more text and code below, but I am mostly trying to understand what this error is telling me - my Google Fu is apparently lacking, and the StackExchange questions I have seen relating to this error seem to be hyper-focused on solving a specific instance of this error. So - What is this error trying to tell me is wrong?

More context. I attempt to execute the PyMultinest (PMN) package as directed in the PMN documentation. PMN is, effectively, a Python wrapper for a C program. Running PMN requires a fair bit of setup code (several ancillary functions need to be defined, as well as a host of variables), which I'm not including here by default because it's ... a lot, but I can if needed. The PMN execution line I use is

pmn.run(Loglike, Prior, ndims, n_live_points=1000, n_params=n_params, outputfiles_basename='./'+ProjectName+'/temp_', resume=False, verbose=True)

This returns the error traceback

File "[redacted]", line 139, in <module>
  pmn.run(Loglike, Prior, ndims, n_live_points=1000, n_params=n_params, outputfiles_basename='./'+ProjectName+'/temp_', resume=False, verbose=True)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pymultinest/run.py", line 254, in run
  lib.run(*args_converted)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/ctypes/__init__.py", line 386, in __getattr__
  func = self.__getitem__(name)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/ctypes/__init__.py", line 386, in __getitem__
  func = self._FuncPtr((name_or_ordinal, self))
AttributeError: dlsym(RTLD_DEFAULT, run): symbol not found

If it helps, I have determined that the name variable being passeed through self.__getitem__(), and thus into self._FuncPtr(), is run. Although, that might be obvious looking at the AttributeError message.

I am running Python 3.8 (as shown above) on a MacOS machine. Last summer, I was able to execute PMN on this machine using extremely similar code to that which I am using now. I am currently trying to optimize my code from last summer, which is why I'm surprised it isn't simply "working".

So far my attempts at fixing this have been mostly centered on reinstalling PMN. I have done a clean install (pip uninstall/pip install) of the PMN package, as well as following the PMN documentation to rebuild the C portion of the package. I have included the source directories of the C software in my Path variables - or at least, I tried to, I am assuming I was successful, but I'm not very familiar with Macs.

Ultimately, I just wish I understood what Python was telling me with this error better. It would help me direct my own attempts at solving the issue. I suspect it is saying "We don't know where to find this 'run' command you're asking for," in which case I need to figure out why my Path variable changes aren't working. Am I on the right path?

Upvotes: 2

Views: 7461

Answers (3)

j13r
j13r

Reputation: 2671

Some hints how to resolve this are given in these issues:

https://github.com/JohannesBuchner/PyMultiNest/issues/160

https://github.com/JohannesBuchner/PyMultiNest/issues/163

It is important to cleanly recompile (empty the build folder) when the environment changes, so that cmake recognises changed libraries and compilers.

Upvotes: 1

Vishal Raj Maurya
Vishal Raj Maurya

Reputation: 1

Run command flutter pub cache clean and flutter clean and after that run flutter pub get now relaunch your emulator it worked for me.

Upvotes: -1

Christijean Lemmens
Christijean Lemmens

Reputation: 1

  1. Check if you are running everything with python3 and not python (works as python 2.x is you have both version 2 and 3 installed)
  2. Check is all the PyMultiNest python files are rewritten in python 3 style, e.g. $ print "something" becomes $ print("something")

My supervisor was accidentally running on python 2.7 and got the same error, so your error might as well be due to mismatch of python version usages.

Upvotes: 0

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