BUG: fix sign(0+0j) to be zero, not nan

closes gh-166

Author: ev-br

array_api_strict/_elementwise_functions.py

@@ -352,5 +352,7 @@ def sign(x: Array, /) -> Array:
         raise TypeError("Only numeric dtypes are allowed in sign")
     # Special treatment to work around non-compliant NumPy 1.x behaviour
     if x.dtype in _complex_floating_dtypes:
-        return x/abs(x)
+        _x = x._array
+        _result = _x / np.abs(np.where(_x != 0, _x, np.asarray(1.0, dtype=_x.dtype)))
+        return Array._new(_result, device=x.device)
     return Array._new(np.sign(x._array), device=x.device)