blepabyte / maxray

Trace and modify the result of (almost) every single expression executed in a Python program

maxray

the problem with doing weird metaprogramming shit is having to deal with other people's weird metaprogramming shit

Trace and modify the result of (almost) every single expression executed in a Python program. WIP.

from maxray import transform, xray, maxray

from torch import tensor, Tensor, device


def move_tensor(x, ctx):
    if isinstance(x, Tensor) and x.device != device("cuda"):
        return x.to("cuda")
    return x


@transform(move_tensor)
def show_multiply(a, b):
    print(a @ b)

# Source code is rewritten to be equivalent to:

def _show_multiply(a, b):
    move_tensor(move_tensor(print, ...)(move_tensor(a, ...) @ move_tensor(b, ...)), ...)

# ---

show_multiply(
    tensor([[0.0, 1.0], [1.0, 1.0]], device="cpu"),
    tensor([[1.0], [1.0]], device="cuda"),
)  # Without the decorator, you'd expect `RuntimeError: Expected all tensors to be on the same device`

# tensor([[1.],
#         [2.]], device='cuda:0')

The *xray decorators will recursively trace and patch every single callable they encounter until reaching either builtins, native, or generated code.

The ctx argument contains context information about the location of the original source code, which may be useful to build editor/LSP integrations.

Installation

pip install maxray

Actively supported Python versions:

• 3.11
• 3.12