Python3 support

[jjnurminen]

Hi,

I have written a library for processing and visualization of 3d gait data that heavily relies on btk Python bindings. I'm planning a transition to Python 3, since major libraries like NumPy are planning to drop Python 2 support soon.

Are there plans to make the btk bindings Python 3 compatible? Would this entail a lot of work?

@Alzathar @aaa34169

[CameronJGrant]

I had the same issue. I ended up rebuilding the package from the source code using the Python 3 libraries. It worked like a charm.

For reference I used:
Windows 10
cmake: 3.15.1
Python: 3.5.3
SWIG: 4.0.0
NumPy: 1.17.0

Since the BTK package relies completely on C++ code, you should be able to easily rebuild the package in any language that is supported by SWIG, including the latest versions of Python.

Just follow the instructions here:
https://biomechanical-toolkit.github.io/docs/API/_build_instructions.html

[jjnurminen]

@CameronJGrant thanks!
There are also rumours about a new PyBTK package on PyPi which supports Python 3.

[aaa34169]

hello As Cameron did, i have just compiled btk source with python3 as target of swig, then collect binaries in a git folder. i ran all unit tests already included in btk. All tests passed :) There is nothing official with pyBTK and dont want to do any support. It s just a folder i might use as third party package of pyCGM2 unless i choose another API ;-) cheers Le mer. 21 août 2019 à 07:47, Jussi Nurminen <[email protected]> a écrit :

…

@CameronJGrant <https://github.com/CameronJGrant> thanks! There are also rumours about a new PyBTK package on PyPi which supports Python 3. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#2?email_source=notifications&email_token=AAXUMBPPH3JRDHP3JAL5VDTQFTQI3A5CNFSM4GDN2TGKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD4YUANA#issuecomment-523321396>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAXUMBPK33RIYVEMZF7H56TQFTQI3ANCNFSM4GDN2TGA> .

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[jjnurminen]

Sorry for the advertisement Fabien ;)

[henrypowell87]

Hi @CameronJGrant. I'm currently trying to get BTKPython running. I have installed BTKCore-Master using cmake and have downloaded the BTKPython-Master repo. I'm not sure where to go from here, though. If I add the bin/ directory to my path using sys in Python (as has been suggested here: http://biomechanical-toolkit.github.io/docs/Wrapping/Python/_getting_started.html) it doesn't find any of the necessary python files. Am I in the right direction here or have I already gone wrong? The link you posted to instructions 404ed for me. Any help would be greatly appreciated. Cheers.

[CameronJGrant]

@henrypowell87
Hi Henry,
Actually, @melund has done some great work creating a Python 3 conda package for btk:
Biomechanical-ToolKit/BTKCore#28

It can be installed through:
conda install -c conda-forge btk

Will that work for you, or do you need to compile things yourself?

[henrypowell87]

@CameronJGrant Thanks for this! After pulling my hair out all day trying to get things working with cmake and the BTK repos I've resorted to a conda install on my work OSX of the ezc3d package (linked here: https://github.com/pyomeca/ezc3d) which I'm currently testing. I'll take a look at the conda btk library you linked as well. Great to hear someone has been working to streamline the btk set up with python (wish I found that 6 hours ago, though!).

Many thanks for getting back so quickly! Cheers.

[melund]

@henrypowell87 I would also suggest that you use ezc3d. It is not as stable as btk, but is actively maintained and it has more pythonic interface.

Also, the btk conda package I made is only for windows. Because that is what I have available, and what I needed.

It can be converted to mac. Probably quite easily. If you have struggled with cmake, then maybe you are the right person to enable mac/linux support for the conda package. See this PR which I have started:

conda-forge/btk-feedstock#4

But again, consider something else if you are starting a new project. The conda package was mostly for supporting my old projects. Now that python2 is dead.

[henrypowell87]

@melund Thanks for this response. I did indeed find ezc3d pretty straight forward to use and, for the time being at least, it's doing the pretty basic job I needed it for. If I run into issues with the stability of the library in the future I'll be sure to looking into working on porting the btk conda package to linux/ OSX. Thanks again for getting back to me.