Carla Python/C++ extension - import error: undefined symbol Ipopt - c++

Question

I implemented a MPC controller within CARLA 0.9.8 trafficmanager. That MPC controller is dependent on IPOPT.
Carla make commands (make rebuild; make PythonAPI) work fine.
However import carla in the python script spawn_npc.py throws the following error:
ImportError: /home/DNDE.EMEA.DENSO/cha/.cache/Python-Eggs/carla-0.9.8-py2.7-linux-x86_64.egg-tmp/carla/libcarla.so: undefined symbol: _ZN5Ipopt16IpoptApplicationC1Ebb
After googling for hours I assume that I have to modify the file setup.py in order to include and link the ipopt library, which is in /usr/local/lib.
But my trial & error procedure was not successful
The setup.py file is:
#!/usr/bin/env python
# Copyright (c) 2019 Computer Vision Center (CVC) at the Universitat Autonoma de
# Barcelona (UAB).
#
# This work is licensed under the terms of the MIT license.
# For a copy, see <https://opensource.org/licenses/MIT>.
from setuptools import setup, Extension
import fnmatch
import os
import platform
import sys
def get_libcarla_extensions():
include_dirs = ['dependencies/include']
library_dirs = ['dependencies/lib']
libraries = []
sources = ['source/libcarla/libcarla.cpp']
def walk(folder, file_filter='*'):
for root, _, filenames in os.walk(folder):
for filename in fnmatch.filter(filenames, file_filter):
yield os.path.join(root, filename)
if os.name == "posix":
# #todo Replace deprecated method.
linux_distro = platform.dist()[0] # pylint: disable=W1505
if linux_distro.lower() in ["ubuntu", "debian", "deepin"]:
pwd = os.path.dirname(os.path.realpath(__file__))
pylib = "libboost_python%d%d.a" % (sys.version_info.major,
sys.version_info.minor)
extra_link_args = [
os.path.join(pwd, 'dependencies/lib/libcarla_client.a'),
os.path.join(pwd, 'dependencies/lib/librpc.a'),
os.path.join(pwd, 'dependencies/lib/libboost_filesystem.a'),
os.path.join(pwd, 'dependencies/lib/libRecast.a'),
os.path.join(pwd, 'dependencies/lib/libDetour.a'),
os.path.join(pwd, 'dependencies/lib/libDetourCrowd.a'),
os.path.join(pwd, 'dependencies/lib', pylib)]
extra_compile_args = [
'-isystem', 'dependencies/include/system', '-fPIC', '-std=c++14',
'-Werror', '-Wall', '-Wextra', '-Wpedantic', '-Wno-self-assign-overloaded',
'-Wdeprecated', '-Wno-shadow', '-Wuninitialized', '-Wunreachable-code',
'-Wpessimizing-move', '-Wold-style-cast', '-Wnull-dereference',
'-Wduplicate-enum', '-Wnon-virtual-dtor', '-Wheader-hygiene',
'-Wconversion', '-Wfloat-overflow-conversion',
'-DBOOST_ERROR_CODE_HEADER_ONLY', '-DLIBCARLA_WITH_PYTHON_SUPPORT'
]
if 'BUILD_RSS_VARIANT' in os.environ and os.environ['BUILD_RSS_VARIANT'] == 'true':
print('Building AD RSS variant.')
extra_compile_args += ['-DLIBCARLA_RSS_ENABLED']
extra_link_args += [os.path.join(pwd, 'dependencies/lib/libad-rss.a')]
if 'TRAVIS' in os.environ and os.environ['TRAVIS'] == 'true':
print('Travis CI build detected: disabling PNG support.')
extra_link_args += ['-ljpeg', '-ltiff']
extra_compile_args += ['-DLIBCARLA_IMAGE_WITH_PNG_SUPPORT=false']
else:
extra_link_args += ['-lpng', '-ljpeg', '-ltiff']
extra_compile_args += ['-DLIBCARLA_IMAGE_WITH_PNG_SUPPORT=true']
# #todo Why would we need this?
include_dirs += ['/usr/lib/gcc/x86_64-linux-gnu/7/include']
library_dirs += ['/usr/lib/gcc/x86_64-linux-gnu/7']
extra_link_args += ['/usr/lib/gcc/x86_64-linux-gnu/7/libstdc++.a']
else:
raise NotImplementedError
elif os.name == "nt":
sources += [x for x in walk('dependencies/include/carla', '*.cpp')]
pwd = os.path.dirname(os.path.realpath(__file__))
pylib = 'libboost_python%d%d' % (
sys.version_info.major,
sys.version_info.minor)
extra_link_args = ['shlwapi.lib' ]
required_libs = [
pylib, 'libboost_filesystem',
'rpc.lib', 'carla_client.lib',
'libpng.lib', 'zlib.lib',
'Recast.lib', 'Detour.lib', 'DetourCrowd.lib']
# Search for files in 'PythonAPI\carla\dependencies\lib' that contains
# the names listed in required_libs in it's file name
libs = [x for x in os.listdir('dependencies/lib') if any(d in x for d in required_libs)]
for lib in libs:
extra_link_args.append(os.path.join(pwd, 'dependencies/lib', lib))
# https://learn.microsoft.com/es-es/cpp/porting/modifying-winver-and-win32-winnt
extra_compile_args = [
'/experimental:external', '/external:I', 'dependencies/include/system',
'/DBOOST_ALL_NO_LIB', '/DBOOST_PYTHON_STATIC_LIB',
'/DBOOST_ERROR_CODE_HEADER_ONLY', '/D_WIN32_WINNT=0x0600', '/DHAVE_SNPRINTF',
'/DLIBCARLA_WITH_PYTHON_SUPPORT', '-DLIBCARLA_IMAGE_WITH_PNG_SUPPORT=true']
else:
raise NotImplementedError
depends = [x for x in walk('source/libcarla')]
depends += [x for x in walk('dependencies')]
def make_extension(name, sources):
return Extension(
name,
sources=sources,
include_dirs=include_dirs,
library_dirs=library_dirs,
libraries=libraries,
extra_compile_args=extra_compile_args,
extra_link_args=extra_link_args,
language='c++14',
depends=depends)
print('compiling:\n - %s' % '\n - '.join(sources))
return [make_extension('carla.libcarla', sources)]
setup(
name='carla',
version='0.9.8',
package_dir={'': 'source'},
packages=['carla'],
ext_modules=get_libcarla_extensions(),
license='MIT License',
description='Python API for communicating with the CARLA server.',
url='https://github.com/carla-simulator/carla',
author='The CARLA team',
author_email='carla.simulator#gmail.com',
include_package_data=True)
includes in MPC.cpp:
#include "carla/trafficmanager/MPC.h"
#include <cppad/cppad.hpp>
#include <cppad/ipopt/solve.hpp>
#include <Eigen-3.3/Eigen/Dense>
includes in MPC.h:
#include <vector>
#include <Eigen-3.3/Eigen/Dense>
#include "carla/trafficmanager/PIDController.h"
#include "carla/client/Vehicle.h"
#include "carla/geom/Math.h"
Can anyone help?

Answer 1

The setup script calls the compiler to generate a shared library. Just modify the extra_link_args to link your library as you would do if you were calling the compiler directly.
Assuming you're using Linux, if you have your library installed in your machine add a -lipopt, in the same way is done with -lpng for libpng. If you have it somewhere not on your system libraries path or want to link statically pass the full path, just as it's done for libcarla_client.a for instance.
Carla uses clang as compiler on Linux, you can check its command-line ref if you want more details.

Answer 2

The recent version of carla was throwing the same error for me after researching for some time ,I have tried this method hope it works for you. First go to the location of the spawn.py folder using command prompt and type the following commands.
py -3.7 spawn.py
It supports only 3.7 version of python .You can refer youtube to understand how to run keep multiple version of python in windows.