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Make PyTensor compatible with numpy 2.0 #1194

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merged 19 commits into from
Feb 17, 2025

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brendan-m-murphy
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@brendan-m-murphy brendan-m-murphy commented Feb 5, 2025

Description

This PR makes PyTensor compatible with numpy versions >= 1.26 and < 2.2. (Numba requires numpy < 2.2.)

These changes include:

  • Unpinning numpy in environment files and pyproject
  • Adding a numpy 1.26 test job to CI
    • runs on python 3.10, float32 0, fast-compile 0
    • skips doctests, since it doesn't seem to easy to make these conditional on numpy version, and the numpy repr for numerical types has changed (e.g. in numpy < 2.0, 3 will print, but in numpy >= 2.0, np.int64(3) will print)
  • General numpy deprecations and namespace changes:
    • updated imports due to changed name spaces (e.g. numpy.core is now numpy._core, and many functions have been moved from core to new public locations like numpy.lib; also AxisError needs to be imported from numpy.exceptions now). These changes are conditional on numpy version number, except the AxisError import, which is compatible with numpy 1.26.
    • deprecations: the main change is that np.cast is deprecated; its replacement is np.asarray(..., dtype=...)
  • The return value of the inverse indices from np.unique has changed when axis is None; this required changes in the Unique Op. (This change is conditional on numpy version number.)
  • Changes in how overflows and type conversions are handled: to explicitly change the type of a numpy array, you must use .astype. Conversions are no longer handled automatically; for instance np.asarray(-1, dtype="unit8") will raise an OverflowError.
    • TensorType.filter uses this new conversion method if allow_downcast is true, which preserves the existing behavior
    • Several tests have been changes to either expect OverflowErrors (for numpy >= 2.0, or TypeError for numpy < 2.0), or use equivalent but valid values (e.g. using 255 for a uint8, instead of -1).
  • Changes to python type promotion (NEP 50)
    • NEP 50 outlines changes in how python types are compared with and converted to numpy types. These changes were optional before numpy 2.0, but are now default. Essentially, the new rule is: if a python float is used in an operation with a numpy float, the type of the numpy float will always be used.
    • The NumpyAutocaster has been changes to explicitly convert values to numpy types using np.asarray, which preserves the existing behavior. (The reason this preserves the behavior is that this is how the comparison is done in TensorType.filter, where np.asarray(data) is compared to converted_data = np.asarray(data, self.dtype).)
  • Changes to random number generators:
    • The numpy PR numpy/numpy@44ba7ca
      changed methods of numpy.random.Generator that are used by copy and pickle.
    • To get a copy of a numpy Generator with independent state, you must use deepcopy now, instead of copy
    • This PR also changed the return value of Generator.__getstate__() to None. To get the state now, you must use Generator.bit_generator.state.
  • Changes due to changes in the numpy C-API
    • Some minor changes with straightforward updates, e.g. replace ->elsize by PyArray_ITEMSIZE
    • Changes to complex scalars in ScalarType. The numpy implementation of complex numbers has been changed from a struct with real and imaginary values to the native C-99 complex types. On disk, these are equivalent, but the real and imaginary parts C-99 complex types cannot be accessed using pointers. Numpy provides some macros to make accessing real and imaginary parts uniform across pre and post 2.0 version. Since these are implemented in terms of the types npy_cfloat, npy_cdouble, npy_clongdouble, some generic functions were added to the C code so that we do not need to explicitly translation bit size aliases ilke npy_complex64 to these types.
    • The constant np.MAXDIMS was removed from the public API. This value was a common flag used to indicate that axis=None has been passed. Now there is an explicitly flag NPY_RAVEL_AXIS. Implementing this change was a bit variable across the affected code. A compatibility header was added to pytensor/npy_2_compat.py to make NPY_RAVEL_AXIS available for numpy < 2.0.
    • MapIter was removed from the public numpy C-API, so it was not possible to adapt the C-code for AdvancedIncSubtensor1; instead a NotImplementedError is raised, so this Op defaults to the python implementation, which uses np.add.at.
  • Dropped support for Python 2 in C code.

Related Issue

Checklist

Type of change

  • New feature / enhancement
  • Bug fix
  • Documentation
  • Maintenance
  • Other (please specify):

📚 Documentation preview 📚: https://pytensor--1194.org.readthedocs.build/en/1194/

@brendan-m-murphy brendan-m-murphy mentioned this pull request Feb 5, 2025
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codecov bot commented Feb 5, 2025

Codecov Report

Attention: Patch coverage is 96.77419% with 5 lines in your changes missing coverage. Please review.

Project coverage is 82.04%. Comparing base (bbe663d) to head (b633bca).
Report is 19 commits behind head on main.

Files with missing lines Patch % Lines
pytensor/sparse/rewriting.py 75.00% 2 Missing ⚠️
pytensor/link/numba/dispatch/random.py 50.00% 1 Missing ⚠️
pytensor/tensor/basic.py 75.00% 1 Missing ⚠️
pytensor/tensor/type.py 90.00% 1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (96.77%) is below the target coverage (100.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

Impacted file tree graph

@@            Coverage Diff             @@
##             main    #1194      +/-   ##
==========================================
+ Coverage   82.01%   82.04%   +0.03%     
==========================================
  Files         187      188       +1     
  Lines       48467    48533      +66     
  Branches     8669     8675       +6     
==========================================
+ Hits        39749    39819      +70     
+ Misses       6554     6553       -1     
+ Partials     2164     2161       -3     
Files with missing lines Coverage Δ
pytensor/link/c/basic.py 87.72% <100.00%> (+0.24%) ⬆️
pytensor/link/c/interface.py 90.09% <100.00%> (ø)
pytensor/link/c/lazylinker_c.py 75.30% <100.00%> (ø)
pytensor/link/jax/dispatch/random.py 93.70% <100.00%> (ø)
pytensor/link/numba/dispatch/elemwise.py 94.67% <100.00%> (ø)
pytensor/npy_2_compat.py 100.00% <100.00%> (ø)
pytensor/scalar/basic.py 80.68% <100.00%> (+0.09%) ⬆️
pytensor/sparse/basic.py 82.57% <100.00%> (ø)
pytensor/tensor/blas.py 73.95% <100.00%> (ø)
pytensor/tensor/blas_headers.py 70.78% <100.00%> (ø)
... and 16 more

@ricardoV94
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Numba requires numpy < 2.2.

Numba is an optional dependency for us so no need to pin, we can just make sure the CI runs with that version for the numba + benchmark tests (they are already separate)

@ricardoV94
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PS: this is amazing 😍 I'll try to review soon

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ricardoV94 commented Feb 5, 2025

We'll need to advertise slower advanced indexing operation on the C backend. I think that's the only regression?

@brendan-m-murphy
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We'll need to advertise slower advanced indexing operation on the C backend. I think that's the only regression?

Yes, it np.add.at is possibly slower in some cases: aesara-devs/aesara#1506. There is an open issue tracking enhancements: numpy/numpy#23176

I haven't looked at any benchmarks for this change, so I'm not sure what the impact is.

I'm making some changes to unpin numpy and make sure the CI runs with 2.1 for numba, I'll push those today.

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brendan-m-murphy commented Feb 6, 2025

@ricardoV94 Okay, unpinned numpy and changed the CI to match. I ran the tests on my fork and they passed. There was some random mypy issue, so I've fixed that. Not sure why it was raised now.

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@brendan-m-murphy Thanks for this pull request! Looking forward to it!

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This looks great, some small comments / questions

@ricardoV94 ricardoV94 changed the title Numpy 2.0 updates Make PyTensor compatible with numpy 2.0 Feb 11, 2025
@brendan-m-murphy brendan-m-murphy force-pushed the numpy-2-updates branch 3 times, most recently from 340f24c to e7b728f Compare February 14, 2025 14:11
@brendan-m-murphy
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This looks great, some small comments / questions

Okay, I think I've addressed everything. (Sorry I didn't realise when I was pushing to my fork that it was pushing here too... but the latest push should pass CI.)

I've moved most of the numpy-version conditional code to npy_2_compat.py, I changed Unique to have the same behavior as in numpy < 2.0, and I made the other changes we discussed above.

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maresb commented Feb 14, 2025

@brendan-m-murphy, just in case you didn't notice there's a merge conflict.

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@brendan-m-murphy, just in case you didn't notice there's a merge conflict.

Thanks, I rebased onto main, should be good now.

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maresb commented Feb 14, 2025

@brendan-m-murphy, looks like there's still an unresolved merge conflict in your copy of pyproject.toml:

pytensor/pyproject.toml

Lines 131 to 136 in ecfd045

[tool.ruff.lint]
<<<<<<< HEAD
select = ["B905", "C", "E", "F", "I", "UP", "W", "RUF", "PERF", "PTH", "ISC", "T20"]
=======
select = ["B905", "C", "E", "F", "I", "UP", "W", "RUF", "PERF", "PTH", "ISC", "NPY201"]
>>>>>>> ca2dd3dce (Unpinned numpy)

@ricardoV94
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ricardoV94 commented Feb 14, 2025

@brendan-m-murphy It seems you resolved all the comments, so we're pretty much ready to merge once those last conflicts get solved!.

I will give another pass next week to see if we didn't miss anything else.

Repeating myself, but this is an incredible contribution 🙏

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Good news is all tests are passing!

@jessegrabowski
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sorry team :(

ricardoV94 and others added 19 commits February 17, 2025 15:31
- replaced np.AxisError with np.exceptions.AxisError
- the `numpy.core` submodule has been renamed to `numpy._core`
- some parts of `numpy.core` have been moved to `numpy.lib.array_utils`

Except for `AxisError`, the updated imports are conditional on
the version of numpy, so the imports should work for numpy >= 1.26.

The conditional imports have been added to `npy_2_compat.py`, so the
imports elsewhere are unconditonal.
- Replace np.cast with np.asarray: in numpy 2.0,
  `np.cast[new_dtype](arr)` is deprecated.
  The literal replacement is `np.asarray(arr, dtype=new_dtype)`.

- Replace np.sctype2char and np.obj2sctype.
  Added try/except to handle change in behavior
  of `np.dtype`

- Replace np.find_common_type with np.result_type

Further changes to `TensorType`:

TensorType.dtype must be a string, so the code
has been changed from `self.dtype = np.dtype(dtype).type`,
where the right-hand side is of type `np.generic`, to
`self.dtype = str(np.dtype(dtype))`, where the right-hand
side is a string that satisfies:

`self.dtype == str(np.dtype(self.dtype))`

This doesn't change the behavior of `np.array(..., dtype=self.dtype)`
etc.
Some macros were removed from npy_3k_compat.h.
Following numpy, I updated the affected functions
to the Python 3 names, and removed support for Python 2.

Also updated lazylinker_c version to indicate substantial changes to the
C code.
- replace `->elsize` by `PyArray_ITEMSIZE`
- don't use deprecated PyArray_MoveInto
Anything `Hashable` should work, but I've made the
return type `tuple[Hashable]` to keep with the current style.

This means, e.g., we can use strings in the cache version.
This is done using C++ generic functions
to get/set the real/imag parts of complex numbers.

This gives us an easy way to support Numpy v < 2.0,
and allows the type underlying the bit width types,
like pytensor_complex128, to be correctly inferred
from the numpy complex types they inherit from.

Updated pytensor_complex struct to use get/set real/imag
aliases defined above. Also updated operators such as
`Abs` to use get_real, get_imag.

Macros have been added to ensure compatibility with numpy < 2.0

Note: redefining the complex arithmetic here means that we
aren't treating NaNs and infinities as carefully as the C99
standard suggets (see Appendix G of the standard).

The code has been like this since it was added to Theano,
so we're keeping the existing behavior.
MapIter was removed from the public numpy C-API in
version 2.0, so we raise a not implemented error to
default to the python code for the AdvancedInSubtensor1.

The python version, defined in `AdvancedInSubtensor1.perform`
calls `np.add.at`, which uses `MapIter` behind the scenes.
There is active development on Numpy to improve the efficiency
of `np.add.at`.

To skip the C implementation and use the Python implementation,
we raise a NotImplementedError for this op's c code if numpy>=2.0.
This was done for the python linker and numba linker.

deepcopy seems to be the recommended method for
copying a numpy Generator.

After this numpy PR:
numpy/numpy@44ba7ca
`copy` didn't seem to actually make an independent copy of
the `np.random.Generator` objects spawned by `RandomStream`.

This was causing the "test values" computed by e.g.
`RandomStream.uniform` to increment the RNG state, which
was causing tests that rely on `RandomStream` to fail.

Here is some related discussion:
numpy/numpy#24086

I didn't see any official documentation about
a change in numpy that would make copy stop
working.
numpy.random.Generator.__getstate__()
now returns none; to see the state of
the bit generator, you need to use
Generator.bit_generator.state.

This change affects `RandomGeneratorType`, and
several of the random tests (including some for Jax.)
`np.MAXDIMS` was removed from the public API and
no replacement is given in the migration docs.

In numpy <= 1.26, the value of `np.MAXDIMS` was 32.
This was often used as a flag to mean `axis=None`.

In numpy >= 2.0, the maximum number of dims of an
array has been increased to 64; simultaneously, a
constant `NPY_RAVEL_AXIS` was added to the C-API to
indicate that `axis=None`.

In most cases, the use of `np.MAXDIMS` to
check for `axis=None` can be replaced by the
new constant `NPY_RAVEL_AXIS`.

To make this constant accessible when using numpy <= 1.26,
I added a function to insert `npy_2_compat.h` into the support
code for the affected ops.
In numpy 2.0, -1 as uint8 is out of bounds, whereas
previously it would be converted to 255.

This affected the test helper function `reduced_bitwise_and`.
The helper function was changed to use 255 instead of -1 if
the dtype was uint8, since this is what is needed to match the
behavior of the "bitwise and" op.

`reduced_bitwise_and` was only used by `TestCAReduce`
in `tests/tensor/test_elemwise.py`, so it was moved
there from `tests/tensor/test_math.py`
1. Changed autocaster due to new promotion rules

With "weak promotion" of python types in Numpy 2.0,
the statement `1.1 == np.asarray(1.1).astype('float32')` is True,
whereas in Numpy 1.26, it was false.

However, in numpy 1.26, `1.1 == np.asarray([1.1]).astype('float32')`
was true, so the scalar behavior and array behavior are the same
in Numpy 2.0, while they were different in numpy 1.26.

Essentially, in Numpy 2.0, if python floats are used in operations
with numpy floats or arrays, then the type of the numpy object will
be used (i.e. the python value will be treated as the type of the numpy
objects).

To preserve the behavior of `NumpyAutocaster` from numpy <= 1.26, I've
added an explicit conversion of the value to be converted to a numpy
type using `np.asarray` during the check that decides what dtype to
cast to.

2. Updates due to new numpy conversion rules for out-of-bounds python
ints

In numpy 2.0, out of bounds python ints will not be automatically
converted, and will raise an `OverflowError` instead.
For instance, converting 255 to int8 will raise an error, instead of
returning -1.

To explicitly force conversion, we must use
`np.asarray(value).astype(dtype)`, rather than
`np.asarray(value, dtype=dtype)`.

The code in `TensorType.filter` has been changed to the new recommended
way to downcast, and the error type caught by some tests has been
changed to OverflowError from TypeError
I was getting a NameError from the list
comprehensions saying that e.g. `pytensor_scalar`
was not defined. I'm not sure why, but this is another
(more verbose) way to do the same thing.
From numpy PR numpy/numpy#22449,
the repr of scalar values has changed, e.g. from "1" to
"np.int64(1)", which caused two doctests to fail.
In numpy 2.0, if axis=None, then np.unique
does not flatten the inverse indices returned
if return_inverse=True

A helper function has been added to npy_2_compat.py
to mimic the output of `np.unique` from version of
numpy before 2.0
Due to changes in numpy conversion rules (NEP 50),
overflows are not ignored; in particular, negating
a unsigned int causes an overflow error.

The test for `neg` has been changed to check that
this error is raised.
I split this test up to test uint64 separately, since
this is the case discussed in Issue pymc-devs#770. I also added
a test for the exact example used in that issue.

The uint dtypes with lower precision should pass.

The uint64 case started passing for me locally on Mac OSX,
but still fails on CI. I'm not sure why this is, but at
least the test will be more specific now if it fails in the future.
Also added ruff numpy2 transition rule.
Remaining tests now run on latest numpy,
except for Numba jobs, which need numpy 2.1.0
@brendan-m-murphy
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I rebased onto main, it doesn't look like there were any serious conflicts :)

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maresb commented Feb 17, 2025

All green except for codecov. Quick, let's get this in! 😀

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codecov is never green

@ricardoV94 ricardoV94 merged commit 51ea1a0 into pymc-devs:main Feb 17, 2025
72 of 73 checks passed
@maresb maresb mentioned this pull request Feb 17, 2025
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twiecki commented Feb 19, 2025

This is a meaty one - congrats!

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Test on numpy 2.0
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