Library import errors: libpoppler.so.91 and libtbb.so.2 (solved)

[Darius Culvenor]

Greetings PyLidar community, 

I recently installed PyLidar on an Amazon EC2 linux instance using Conda. PyLidar was installed successfully but I encountered a problem with a shared object library which was preventing PyLidar from executing. This has now been resolved and I have described the solution below in case someone else encounters the same issue:

Command: pylidar_test -i testdata_10.tar.bz2

Error returned: ImportError: libpoppler.so.91: cannot open shared object file: No such file or directory

Solution: Run the command “conda config --set channel_priority strict”, then run “conda update pylidar”

In my case, this resulted in some packages required by PyLidar being downgraded, some new packages being installed and some existing packages superseded by a higher-priority channel. This resolved the libpoppler.so.91 error. Setting Conda channel priority to ‘strict’ requires Conda version >= 4.6. There is more information here: https://conda-forge.org/docs/user/tipsandtricks.html

After re-running the pylidar_test command I encountered a second error:

Command: pylidar_test -i testdata_10.tar.bz2

Error returned: ImportError: libtbb.so.2: cannot open shared object file: No such file or directory

Solution: Manually install libtbb. This command worked for me “conda install tbb tbb-devel tbb4py” although it is likely that only ‘tbb’ is required. 

PyLidar is now working as expected. I now have pylidar version 4.4, poppler v0.87.0, python v3.8.10, tbb v2020.2. The operating system is Amazon Linux 2 and kernel version is Linux 4.14.238-182.422.amzn2.x86_64.

I hope this may be of help to someone.

Darius.