Sort fails from lack of comparison function

[dlakaplan]

from numpy_quaddtype import QuadPrecDType, QuadPrecision
import numpy as np

x=np.array([1,2,3], dtype=QuadPrecDType())
i=np.argsort(x)

fails for me (numpy version 2.5.0.dev0+git20260109.f254f12) because of a lack of comparison function:

In [3]: np.argsort(x)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
File ~/miniforge3/envs/nptest2/lib/python3.13/site-packages/numpy/_core/fromnumeric.py:54, in _wrapfunc(obj, method, *args, **kwds)
     53 try:
---> 54     return bound(*args, **kwds)
     55 except TypeError:
     56     # A TypeError occurs if the object does have such a method in its
     57     # class, but its signature is not identical to that of NumPy's. This
   (...)     61     # Call _wrapit from within the except clause to ensure a potential
     62     # exception has a traceback chain.

TypeError: type does not have compare function

During handling of the above exception, another exception occurred:

TypeError                                 Traceback (most recent call last)
Cell In[3], line 1
----> 1 np.argsort(x)

File ~/miniforge3/envs/nptest2/lib/python3.13/site-packages/numpy/_core/fromnumeric.py:1213, in argsort(a, axis, kind, order, stable)
   1100 @array_function_dispatch(_argsort_dispatcher)
   1101 def argsort(a, axis=-1, kind=None, order=None, *, stable=None):
   1102     """
   1103     Returns the indices that would sort an array.
   1104 
   (...)   1211 
   1212     """
-> 1213     return _wrapfunc(
   1214         a, 'argsort', axis=axis, kind=kind, order=order, stable=stable
   1215     )

File ~/miniforge3/envs/nptest2/lib/python3.13/site-packages/numpy/_core/fromnumeric.py:63, in _wrapfunc(obj, method, *args, **kwds)
     54     return bound(*args, **kwds)
     55 except TypeError:
     56     # A TypeError occurs if the object does have such a method in its
     57     # class, but its signature is not identical to that of NumPy's. This
   (...)     61     # Call _wrapit from within the except clause to ensure a potential
     62     # exception has a traceback chain.
---> 63     return _wrapit(obj, method, *args, **kwds)

File ~/miniforge3/envs/nptest2/lib/python3.13/site-packages/numpy/_core/fromnumeric.py:43, in _wrapit(obj, method, *args, **kwds)
     40 # As this already tried the method, subok is maybe quite reasonable here
     41 # but this follows what was done before. TODO: revisit this.
     42 arr, = conv.as_arrays(subok=False)
---> 43 result = getattr(arr, method)(*args, **kwds)
     45 return conv.wrap(result, to_scalar=False)

TypeError: type does not have compare function

Let me know if I'm doing something wrong here. Otherwise thanks for investigating.

[SwayamInSync]

Hi @dlakaplan thanks for reporting it,
we are missing the implementation of NPY_DT_PyArray_ArrFuncs_compare slot, it handle the sorting related methods. I'll add it and then this will be good to go.