ENH: add numerical constants (#51)

Author: person142

numpy-stubs/__init__.pyi

@@ -571,5 +571,21 @@ def isclose(
 def array_equal(a1: _ArrayLike, a2: _ArrayLike) -> bool: ...
 def array_equiv(a1: _ArrayLike, a2: _ArrayLike) -> bool: ...
 
+# Numerical constants
+Inf: float
+Infinity: float
+NAN: float
+NINF: float
+NZERO: float
+NaN: float
+PINF: float
+PZERO: float
+e: float
+euler_gamma: float
+inf: float
+infty: float
+nan: float
+pi: float
+
 # TODO(shoyer): remove when the full numpy namespace is defined
 def __getattr__(name: str) -> Any: ...

tests/reveal/constants.py

@@ -0,0 +1,16 @@
+import numpy as np
+
+reveal_type(np.Inf)  # E: float
+reveal_type(np.Infinity)  # E: float
+reveal_type(np.NAN)  # E: float
+reveal_type(np.NINF)  # E: float
+reveal_type(np.NZERO)  # E: float
+reveal_type(np.NaN)  # E: float
+reveal_type(np.PINF)  # E: float
+reveal_type(np.PZERO)  # E: float
+reveal_type(np.e)  # E: float
+reveal_type(np.euler_gamma)  # E: float
+reveal_type(np.inf)  # E: float
+reveal_type(np.infty)  # E: float
+reveal_type(np.nan)  # E: float
+reveal_type(np.pi)  # E: float