make all fails to build on ubuntu 20.04 due to missing tensorflow-gpu version for Python 3.8 about ocrd_all

[kba]

There is no version of tensorflow-gpu for py38 though, that is the issue here IIUC.

Yup, tensorflow supports python 3.8 only for 2.2.+

[cneud]

@kba Well spotted! Just edited the issue to include Python version = 3.8.

[kba]

Unless the tensorflow people decide to backport 3.8 support for 1.15.*, I see little we can do unfortunately, except upgrade the code to use tf 2.2+.

[cneud]

Yup, tensorflow supports python 3.8 only for 2.2.+

Ok so for 20.04 then we have to wait whether tf will provide packages of 1.15.* also with support for Python 3.8.

[cneud]

except upgrade the code to use tf 2.2+.

Yup, another reason to migrate to tf2.x.

I am closing this now, but we should probably make supported Python versions known in the docs.

[bertsky]

Ok so for 20.04 then we have to wait whether tf will provide packages of 1.15.* also with support for Python 3.8.

Either that or build TF yourself. (Be warned though: it takes ages and often does not work out of the box, esp. on new platforms.)

[bertsky]

Yup, another reason to migrate to tf2.x.

I don't think this is coming any time soon for some of our modules. TF made it really hard to port some ways of writing optimisers etc. And they keep making major modifications even within TF2. Plus all models will have to be re-trained.

[cneud]

build TF yourself

Will have to anyway for qurator ;)