update ocrd_pc_segmentation, move from tf21 to tf2

[bertsky]

To prevent pc_segmentation from dragging in TF 2.5 and thus invalidating that venv for other modules.

[bertsky]

See ocr-d-modul-2-segmentierung/page-segmentation#4 for details.

[bertsky]

Damn. Placing ocrd_pc_segmentation in sub-venv/headless-tf2 creates another conflict around h5py (ocrd_calamari wants <3, but ocr4all-pixel-classifier drags in 3.1).

[bertsky]

Placing ocrd_pc_segmentation in sub-venv/headless-tf2 creates another conflict around h5py (ocrd_calamari wants <3, but ocr4all-pixel-classifier drags in 3.1).

It's not ocrd_pc_segmentation's or ocr4all-pixel-classifier's fault: they simply allow running the most recent TF, which happens to be incompatible with current ocrd_calamari. Unfortunately, the latter does not advertise this dependency. (See fix for the latter here and analysis of the former here.)

I see no way around this other than using different venvs for ocrd_calamari (headless-tf24) and ocrd_pc_segmentation (headless-tf2) – which will cost us another 2GB in the maximum image.

Unless anyone has a better idea?

[kba]

To summarize:

• With h5py == 3.1 and tf == 2.5, calamari still loads models w/o str/unicode issues
• consequently ocrd_calamari also does not need h5py < 3 or tf < 2.5
• ocrd_calamari can be moved to tf2 and the h5py downgrade is redundant

So, we need a new release of ocrd_calamari and the only remaining tf21 processor would be ocrd_anybaseocr?

[bertsky]

To summarize:

• With h5py == 3.1 and tf == 2.5, calamari still loads models w/o str/unicode issues

yes

• consequently ocrd_calamari also does not need h5py < 3 or tf < 2.5

yes

• ocrd_calamari can be moved to tf2

no, ocrd_calamari is already in headless-tf2, but it can stay there along with ocrd_pc_segmentation if ...

and the h5py downgrade is redundant

yes, the combination h5py<3 and TF<2.5 is overly restrictive, and prevents sharing the venv with ocrd_pc_segmentation. (We would need a tf24 venv for no gain.)

So, we need a new release of ocrd_calamari and the only remaining tf21 processor would be ocrd_anybaseocr?

yes

[bertsky]

Ok, I have removed the h5py hack for headless-tf2 and switched to OCR-D/ocrd_calamari@76b34c5 now – let's see if it works.

[bertsky]

Ok, I have removed the h5py hack for headless-tf2 and switched to OCR-D/ocrd_calamari@76b34c5 now – let's see if it works.

No. Seems like ocrd_pc_segmentation needs another fix. Let's see...