pymc-devs/pytensor

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PyTensor allows you to define, optimize, and efficiently evaluate mathematical expressions involving multi-dimensional arrays.

Stars: 644
Forks: 209
Open beginner issues: 4
Indexed issues: 341
Avg merge: 2d 14h
Merged PRs (30d): 16

Dominant language: Python
License: No license data
Last GitHub push: Sep 18, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted

Beginner friendly Everything

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341 open issues indexed

DOC: document f.trust_input=True as MLX hot-loop performance tip Open

docs mlx

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

pymc-devs/pytensor#2093 · Opened Apr 28, 2026
PERF: map pt.logsumexp pattern to native mx.logsumexp (1.5× speedup) Open

enhancement graph rewriting mlx

Difficulty 4/5 3-5 days Newbie friendliness 48/100

pymc-devs/pytensor#2091 · Opened Apr 28, 2026
PERF: detect scaled-dot-product-attention pattern and lower to mx.fast.scaled_dot_product_attention Open

enhancement graph rewriting mlx

Difficulty 4/5 3-5 days Newbie friendliness 55/100

pymc-devs/pytensor#2090 · 1 comment · Opened Apr 28, 2026
PERF: TensorType.filter is O(N) for foreign array types (mx.array, jax.Array, torch.Tensor) Open

backend compatibility enhancement jax mlx

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

pymc-devs/pytensor#2087 · Opened Apr 28, 2026
MLX improvements: meta issue tracking backend perf and correctness Open

backend compatibility enhancement mlx

Difficulty 5/5 Over a week Newbie friendliness 35/100

pymc-devs/pytensor#2085 · 15 comments · 1 reaction · Opened Apr 28, 2026
BUG: `JAXOp.grad` fails when inputs include integer-typed tensors Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 48/100

pymc-devs/pytensor#2072 · 1 comment · Opened Apr 25, 2026
Constant.signature() is broken or missing for several subclasses Open

bug graph objects

Difficulty 4/5 3-5 days Newbie friendliness 42/100

pymc-devs/pytensor#2044 · 1 comment · Opened Apr 11, 2026
CDataTypeConstant.signature() is wrong, merge_signature override shouldn't be needed Open

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

pymc-devs/pytensor#2031 · Opened Apr 6, 2026
Add a type converter registry to Type to replace cross-package deferred imports Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

pymc-devs/pytensor#2029 · Opened Apr 5, 2026
Scan untraced_sit_sot inplace on python/cython backend Open

C-backend memory opt scan

Difficulty 4/5 3-5 days Newbie friendliness 48/100

pymc-devs/pytensor#2025 · Opened Apr 1, 2026
Add MLX GEMM dispatch Open

graph rewriting linalg mlx Op implementation

Difficulty 4/5 3-5 days Newbie friendliness 48/100

pymc-devs/pytensor#2008 · 7 comments · Opened Mar 29, 2026
Reduce status of C backend to "just another backend" Open

C-backend maintenance major request discussion

Difficulty 5/5 Over a week Newbie friendliness 25/100

pymc-devs/pytensor#2006 · 2 comments · Opened Mar 29, 2026
`Blockwise{Convolve1d}` never infers static output shape Open

shape inference

Difficulty 3/5 1-2 days Newbie friendliness 58/100

pymc-devs/pytensor#1998 · 2 comments · Opened Mar 24, 2026
DOC: does the copyright year need to be updated? Open

docs

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

pymc-devs/pytensor#2000 · 11 comments · Opened Mar 20, 2026
Flaky tests/tensor/rewriting/test_math.py::TestExpLog::test_log1mexp_log Open

GitHub CI/CD

Difficulty 3/5 1-2 days Newbie friendliness 35/100

pymc-devs/pytensor#1989 · Opened Mar 18, 2026
Include all failed tests in `all_tests` Open

GitHub CI/CD

Difficulty 3/5 1-2 days Newbie friendliness 35/100

pymc-devs/pytensor#1969 · 2 comments · Opened Mar 12, 2026
Add/Mul fusion does not reason about broadcasting Open

graph rewriting performance

Difficulty 4/5 3-5 days Newbie friendliness 48/100

pymc-devs/pytensor#1966 · 5 comments · Opened Mar 10, 2026
New Scan API Open

request discussion scan

Difficulty 5/5 Over a week Newbie friendliness 35/100

pymc-devs/pytensor#1940 · 4 comments · Opened Mar 6, 2026
CI Crashed process running `tests/link/jax/test_scan.py::test_higher_order_derivatives ` Open

GitHub CI/CD help wanted jax

Difficulty 3/5 1-2 days Newbie friendliness 52/100

pymc-devs/pytensor#1938 · 1 comment · Opened Mar 5, 2026
ENH: Add slogdet rewrite for block diagonal matrices Open

Difficulty 3/5 1-2 days Newbie friendliness 55/100

pymc-devs/pytensor#1921 · 1 comment · Opened Feb 28, 2026
float with 0 decimal converted to float32 instead of float64 Open

bug NumPy compatibility

Difficulty 3/5 1-2 days Newbie friendliness 38/100

pymc-devs/pytensor#1913 · 5 comments · Opened Feb 24, 2026
Advanced(Inc)Subtensor text representation Open

beginner friendly indexing Op implementation

Difficulty 3/5 1-2 days Newbie friendliness 45/100

pymc-devs/pytensor#1906 · 2 comments · Opened Feb 21, 2026
BUG: pt.roll crashes JAX backend JIT compilation due to dynamic slicing Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

pymc-devs/pytensor#1899 · 14 comments · Opened Feb 19, 2026
ENH: Extend linear algebra graph rewrites to cover additional inverse and matmul patterns Open

feature request

Difficulty 4/5 3-5 days Newbie friendliness 45/100

pymc-devs/pytensor#1893 · 6 comments · Opened Feb 19, 2026
Parametrize Alloc by the dimensions that are actually broadcasted Open

Difficulty 5/5 Over a week Newbie friendliness 28/100

pymc-devs/pytensor#1886 · 3 comments · Opened Feb 12, 2026
Reorganize `pytensor/link/numba/dispatch/sparse/math.py` Open

maintenance numba sparse variables

Difficulty 4/5 3-5 days Newbie friendliness 38/100

pymc-devs/pytensor#1874 · Opened Feb 2, 2026
Should PyTensor extend its Numba overloads to support all `scipy.sparse.cs[r|c]_matrix` initialization modes? Open

numba request discussion sparse variables

Difficulty 5/5 Over a week Newbie friendliness 25/100

pymc-devs/pytensor#1872 · 1 comment · Opened Feb 1, 2026
`pytensor.sparse.dot` returns a dense matrix even when both inputs are sparse Open

gradients graph rewriting request discussion sparse variables

Difficulty 3/5 1-2 days Newbie friendliness 48/100

pymc-devs/pytensor#1855 · 5 comments · Opened Jan 21, 2026
Move the `Reshape` Op and `reshape` helper to `reshape.py` Open

beginner friendly help wanted maintenance

Difficulty 2/5 1-3 hours Newbie friendliness 35/100

pymc-devs/pytensor#1852 · 3 comments · Opened Jan 18, 2026
Rewrite `argmax(f(x)` -> argmax(x)` for monotonic f Open

graph rewriting

Difficulty 5/5 Over a week Newbie friendliness 35/100

pymc-devs/pytensor#1851 · 9 comments · 2 reactions · Opened Jan 17, 2026
Batched dot doesn't support complex inputs Open

help wanted linalg NumPy compatibility

Difficulty 3/5 1-2 days Newbie friendliness 43/100

pymc-devs/pytensor#1849 · 1 comment · Opened Jan 16, 2026
Consider adding alternative axis argument to `unpack` Open

Op implementation request discussion

Difficulty 5/5 Over a week Newbie friendliness 25/100

pymc-devs/pytensor#1845 · 1 comment · Opened Jan 12, 2026
Generalize (join|split)_dims to work with arbitrary axes locations Open

enhancement request discussion

Difficulty 5/5 Over a week Newbie friendliness 35/100

pymc-devs/pytensor#1844 · 1 comment · Opened Jan 12, 2026
Remove scipy version pin in CI Open

GitHub CI/CD linalg memory opt SciPy compatibility

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

pymc-devs/pytensor#1841 · Opened Jan 12, 2026
Expand local_block_diag_dot_to_dot_block_diag Open

graph rewriting linalg

Difficulty 4/5 3-5 days Newbie friendliness 35/100

pymc-devs/pytensor#1838 · 6 comments · Opened Jan 11, 2026
Improve IfElse inplace logic to support viewing multiple branches or prioritized aliasing Open

memory opt Op implementation

Difficulty 5/5 Over a week Newbie friendliness 35/100

pymc-devs/pytensor#1811 · Opened Jan 2, 2026
BUG: Multiprocessing and caching with mixed versions Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 25/100

pymc-devs/pytensor#1808 · Opened Jan 2, 2026
Rewrite solve and dot with diagonal matrices Open

graph rewriting linalg

Difficulty 5/5 Over a week Newbie friendliness 35/100

pymc-devs/pytensor#1791 · 1 comment · Opened Dec 15, 2025
Flaky `tests/tensor/signal/test_conv.py::test_batched_1d_agrees_with_2d_row_filter[fft-full]` Open

tests

Difficulty 3/5 1-2 days Newbie friendliness 35/100

pymc-devs/pytensor#1789 · Opened Dec 14, 2025
More debug options when mode=NUMBA Open

enhancement numba

Difficulty 4/5 3-5 days Newbie friendliness 35/100

pymc-devs/pytensor#1787 · 1 comment · Opened Dec 14, 2025
Reconsider handlig of constants in numba backend Open

backend compatibility numba

Difficulty 5/5 Over a week Newbie friendliness 35/100

pymc-devs/pytensor#1759 · Opened Nov 30, 2025
Outdated config docs Open

docs

Difficulty 3/5 1-2 days Newbie friendliness 45/100

pymc-devs/pytensor#1753 · 1 reaction · Opened Nov 27, 2025
Rethink Scan special behavior when n_steps < pre-allocated output buffer Open

backend compatibility Op implementation scan

Difficulty 4/5 3-5 days Newbie friendliness 35/100

pymc-devs/pytensor#1741 · Opened Nov 24, 2025
Scan mixing of positive and negative mitmot taps is error-prone Open

backend compatibility Op implementation scan

Difficulty 4/5 3-5 days Newbie friendliness 45/100

pymc-devs/pytensor#1740 · 1 comment · Opened Nov 24, 2025
Switch Unique behavior from numpy < 2.0 to numpy >= 2.0 Open

maintenance NumPy compatibility

Difficulty 2/5 1-3 hours Newbie friendliness 48/100

pymc-devs/pytensor#1739 · 1 reaction · Opened Nov 24, 2025
MLX CI failing Open

help wanted mlx needs info

pymc-devs/pytensor#1724 · 2 comments · 1 reaction · 1 assignee · Opened Nov 16, 2025
PyTorch CI failing Open

GitHub CI/CD help wanted torch

Difficulty 3/5 1-2 days Newbie friendliness 20/100

pymc-devs/pytensor#1723 · Opened Nov 16, 2025
scipy-stubs PR was reverted Open

Difficulty 3/5 1-2 days Newbie friendliness 38/100

pymc-devs/pytensor#1718 · 1 comment · Opened Nov 8, 2025
BUG: "BLAS alone" detection on Windows failing with 32 bit pseudo relocation out of range Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

pymc-devs/pytensor#1695 · Opened Oct 25, 2025
Scans are never constant-folded Open

graph rewriting performance scan

Difficulty 4/5 3-5 days Newbie friendliness 45/100

pymc-devs/pytensor#1688 · Opened Oct 23, 2025

pymc-devs/pytensor

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