🚚 port ma.arg{min,max} and MaskedArray.arg{min,max}

[guan404ming]

• TYP: Type MaskedArray.{argmin, argmax} and np.ma.{argmin, argmax} numpy#28638 - 🚚 port ma.arg{min,max} and MaskedArray.arg{min,max} #468
• Towards port the numpy.ma typing improvements from NumPy #456

[guan404ming]

Hi @jorenham I've completed the migration, but there are still issues with the CI that I can't resolve. I was hoping you could help. It looks like a runtime type error. Thanks!

Stub: in file src/numpy-stubs/ma/__init__.pyi:1176
Overload(def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: None =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[Literal[False], numpy._globals._NoValueType] =) -> numpy.int64, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> Any, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, *, out: _ArrayT`-1, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None], fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None], out: _ArrayT`-1, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1)
Runtime:
def (a, *args, **params)

error: numpy.ma.argmin is not a function
Stub: in file src/numpy-stubs/ma/__init__.pyi:1138
Overload(def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: None =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[Literal[False], numpy._globals._NoValueType] =) -> numpy.int64, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> Any, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, *, out: _ArrayT`-1, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None], fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None], out: _ArrayT`-1, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1)
Runtime:
def (a, *args, **params)

error: numpy.ma.core.argmax is not a function
Stub: in file src/numpy-stubs/ma/core.pyi:1176
Overload(def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: None =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[Literal[False], numpy._globals._NoValueType] =) -> numpy.int64, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> Any, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, *, out: _ArrayT`-1, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None], fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None], out: _ArrayT`-1, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1)
Runtime:
def (a, *args, **params)

error: numpy.ma.core.argmin is not a function
Stub: in file src/numpy-stubs/ma/core.pyi:1138
Overload(def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: None =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[Literal[False], numpy._globals._NoValueType] =) -> numpy.int64, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> Any, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, *, out: _ArrayT`-1, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None], fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None], out: _ArrayT`-1, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1)
Runtime:
def (a, *args, **params)

Found 4 errors (checked 325 modules)
deleted /home/runner/work/numtype/numtype/.venv/lib/python3.13/site-packages/numpy/py.typed (1)
deleted /home/runner/work/numtype/numtype/.venv/lib/python3.13/site-packages/numpy/**/*.pyi ([23](https://github.com/numpy/numtype/actions/runs/14300819613/job/40074866251?pr=468#step:4:24)7)

[jorenham]

Hi @jorenham I've completed the migration, but there are still issues with the CI that I can't resolve. I was hoping you could help. It looks like a runtime type error. Thanks!

Stub: in file src/numpy-stubs/ma/__init__.pyi:1176
Overload(def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: None =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[Literal[False], numpy._globals._NoValueType] =) -> numpy.int64, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> Any, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, *, out: _ArrayT`-1, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None], fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None], out: _ArrayT`-1, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1)
Runtime:
def (a, *args, **params)

error: numpy.ma.argmin is not a function
Stub: in file src/numpy-stubs/ma/__init__.pyi:1138
Overload(def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: None =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[Literal[False], numpy._globals._NoValueType] =) -> numpy.int64, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> Any, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, *, out: _ArrayT`-1, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None], fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None], out: _ArrayT`-1, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1)
Runtime:
def (a, *args, **params)

error: numpy.ma.core.argmax is not a function
Stub: in file src/numpy-stubs/ma/core.pyi:1176
Overload(def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: None =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[Literal[False], numpy._globals._NoValueType] =) -> numpy.int64, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> Any, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, *, out: _ArrayT`-1, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None], fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None], out: _ArrayT`-1, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1)
Runtime:
def (a, *args, **params)

error: numpy.ma.core.argmin is not a function
Stub: in file src/numpy-stubs/ma/core.pyi:1138
Overload(def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: None =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[Literal[False], numpy._globals._NoValueType] =) -> numpy.int64, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, out: None =, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> Any, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None] =, fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None] =, *, out: _ArrayT`-1, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1, def [_ArrayT <: numpy.ndarray[Any, Any]] (a: _ArrayT`-1, axis: Union[typing.SupportsIndex, None], fill_value: Union[Union[complex, bytes, str, numpy.generic[Any]], None], out: _ArrayT`-1, *, keepdims: Union[bool, numpy._globals._NoValueType] =) -> _ArrayT`-1)
Runtime:
def (a, *args, **params)

Found 4 errors (checked 325 modules)
deleted /home/runner/work/numtype/numtype/.venv/lib/python3.13/site-packages/numpy/py.typed (1)
deleted /home/runner/work/numtype/numtype/.venv/lib/python3.13/site-packages/numpy/**/*.pyi ([23](https://github.com/numpy/numtype/actions/runs/14300819613/job/40074866251?pr=468#step:4:24)7)

Ah yes I was afraid that stubtest wouldn't be able to understand these. and I unfortunately was right about that...

If you look at the numpy source, you'll see the problem (
https://github.com/numpy/numpy/blob/69f4df3b67002f537d816468d8b5c29f06d5f8e3/numpy/ma/core.py#L7236-L7237):

argmin = _frommethod('argmin')
argmax = _frommethod('argmax')

Confusingly, _frommethod is a type (https://github.com/numpy/numpy/blob/69f4df3b67002f537d816468d8b5c29f06d5f8e3/numpy/ma/core.py#L7078-L7117):

class _frommethod:
    """
    Define functions from existing MaskedArray methods.

    Parameters
    ----------
    methodname : str
        Name of the method to transform.

    """

    def __init__(self, methodname, reversed=False):
        self.__name__ = methodname
        self.__qualname__ = methodname
        self.__doc__ = self.getdoc()
        self.reversed = reversed

    def getdoc(self):
        "Return the doc of the function (from the doc of the method)."
        meth = getattr(MaskedArray, self.__name__, None) or\
            getattr(np, self.__name__, None)
        signature = self.__name__ + get_object_signature(meth)
        if meth is not None:
            doc = """    %s\n%s""" % (
                signature, getattr(meth, '__doc__', None))
            return doc

    def __call__(self, a, *args, **params):
        if self.reversed:
            args = list(args)
            a, args[0] = args[0], a

        marr = asanyarray(a)
        method_name = self.__name__
        method = getattr(type(marr), method_name, None)
        if method is None:
            # use the corresponding np function
            method = getattr(np, method_name)

        return method(marr, *args, **params)

It is a similar situation as with ufunc, but in this case we only have __call__ to deal with. Given your experience with ufuncs, you're probably able to figure out the solution now. If not, then don't hesitate to ask for another hint.

---

You could also consider splitting this PR, if you feel that that would help.

[jorenham]

Could you also reference the original numpy PR's here, and co-author @MarcoGorelli in 54319e0 (unless he objects)?

[guan404ming]

Thanks for hint, it currently works well now!

[jorenham]

The _frommethod type is not only used for argmin and argmax, but also for count that have a different callable signature. So I was thinking of a more generic approach where by default, the callable signature has a broad "one-size-fits-all" signature, but that can be customized with a more specific callable signature, e.g. with Callable or a callable Protocol.

[guan404ming]

This week is my midterm week haha, I would try fix this at this weekend~

[jorenham]

This week is my midterm week haha, I would try fix this at this weekend~

There's no rush :) Good luck with your midterm!