Error in tangent tutorial notebook: "AttributeError: module 'gast' has no attribute 'Num'"

[dariush-bahrami]

Hi i opened your tutorial notebook and run the cells in notebook. after installing tangent at cell with following code:

import tangent
df = tangent.grad(f)

the following error arises:

AttributeError Traceback (most recent call last)
in ()
----> 1 import tangent
2 df = tangent.grad(f)

3 frames
/usr/local/lib/python3.6/dist-packages/tangent/grammar.py in ()
16 import gast
17
---> 18 LITERALS = (gast.Num, gast.Str, gast.Bytes, gast.Ellipsis, gast.NameConstant)
19
20 CONTROL_FLOW = (gast.For, gast.AsyncFor, gast.While, gast.If, gast.Try)

AttributeError: module 'gast' has no attribute 'Num'

[mdanatg]

This is due to incompatible dependencies. We haven't had the chance to upgrade the code. Could you try installing an older version of gast:

pip install gast==0.2.4

[Pyrofoux]

This yield the issue:

ERROR: Could not find a version that satisfies the requirement gast==0.2.4 (from versions: 0.1, 0.1.1, 0.1.2, 0.1.3, 0.1.4, 0.1.5, 0.2.0, 0.2.1, 0.2.1.post0, 0.2.1.post1, 0.2.2, 0.3.0, 0.3.1, 0.3.2, 0.3.3, 0.4.0, 0.5.0, 0.5.1, 0.5.2, 0.5.3)
ERROR: No matching distribution found for gast==0.2.4

Looks like there's no gast 0.2.4.

Using 0.3.0 yields

[/usr/local/lib/python3.7/dist-packages/tangent/grammar.py](https://localhost:8080/#) in <module>()
     16 import gast
     17 
---> 18 LITERALS = (gast.Num, gast.Str, gast.Bytes, gast.Ellipsis, gast.NameConstant)
     19 
     20 CONTROL_FLOW = (gast.For, gast.AsyncFor, gast.While, gast.If, gast.Try)

AttributeError: module 'gast' has no attribute 'Num'

while using 0.2.2 yields

[/usr/local/lib/python3.7/dist-packages/tangent/tf_extensions.py](https://localhost:8080/#) in <module>()
     58 
     59 non_differentiable.register_non_differentiable_functions(
---> 60     tf.shape, tf.to_float, tf.equal, tf.constant,
     61     tf.zeros, tf.ones, tf.zeros_like, tf.ones_like,
     62     size, shape_as_list, dtype)

AttributeError: module 'tensorflow' has no attribute 'to_float'

All these examples are from the Colab notebook. It's such a shame Tangent isn't functional anymore, it would have been pretty useful.

[mdanatg]

Odd that that version is gone. Does 0.2.2 work instead?

[Pyrofoux]

No, both 0.3.0 and 0.2.2 do not work. My previous comment contains errors for both versions!

[mdanatg]

That means that the code would need to be upgraded to the newest version. Not terribly difficult, it's mostly mechanical, if anyone has the bandwitdth to do it.

[smbarr]

I took a stab at upgrading to gast 0.3.0 in smbarr/tangent-upgrade-gast

Most of the tests seem to be passing now, but I'm having a lot of trouble getting some of the tensorflow derivatives to work.

I would really like to get all the tests passing, so if anyone has an idea of how to do that I'm happy to help further. This is a really interesting and unique project which I'd hate to see die.