put cbrt() in utils.py

Author: scivision

src/pymap3d/spherical.py

@@ -14,18 +14,14 @@
         degrees,
         arctan2 as atan2,
         sqrt,
-        cbrt,
         power as pow,
     )
 except ImportError:
     from math import radians, sin, hypot, degrees, atan2, asin, sqrt  # type: ignore
 
-    def cbrt(x):  # type: ignore
-        "Backup cube root function in case of no numpy"
-        return x ** (1 / 3)
 
 from .ellipsoid import Ellipsoid
-from .utils import sanitize
+from .utils import sanitize, cbrt
 
 
 __all__ = [
@@ -87,7 +83,8 @@ def geodetic2spherical(
 
     # radius of curvature of the prime vertical section
     N = ell.semimajor_axis**2 / hypot(
-        ell.semimajor_axis * coslat, ell.semiminor_axis * sinlat,
+        ell.semimajor_axis * coslat,
+        ell.semiminor_axis * sinlat,
     )
 
     # Instead of computing X and Y, we only compute the projection on the XY

src/pymap3d/tests/test_spherical.py

@@ -2,13 +2,14 @@
 from pytest import approx
 
 try:
-    import numpy.array as nparray
+    from numpy import asarray
 except ImportError:
 
-    def nparray(*args):
+    def asarray(*args):  # type: ignore
         "dummy function to convert values to arrays"
         return args
 
+
 import pymap3d as pm
 
 
@@ -36,8 +37,8 @@ def nparray(*args):
 ]
 llallr_list = [([[i] for i in lla], llr) for lla, llr in llallr]
 llrlla_list = [([[i] for i in llr], lla) for llr, lla in llrlla]
-llallr_array = [([nparray(i) for i in lla], llr) for lla, llr in llallr]
-llrlla_array = [([nparray(i) for i in llr], lla) for llr, lla in llrlla]
+llallr_array = [([asarray(i) for i in lla], llr) for lla, llr in llallr]
+llrlla_array = [([asarray(i) for i in llr], lla) for llr, lla in llrlla]
 
 atol_dist = 1e-6  # 1 micrometer
 

src/pymap3d/utils.py

@@ -8,7 +8,7 @@
 from .ellipsoid import Ellipsoid
 
 try:
-    from numpy import hypot, cos, sin, arctan2 as atan2, radians, asarray, sign
+    from numpy import hypot, cos, sin, arctan2 as atan2, radians, asarray, sign, cbrt
 except ImportError:
     from math import atan2, hypot, cos, sin, radians  # type: ignore
 
@@ -23,6 +23,10 @@ def sign(x) -> float:  # type: ignore
 
         return y
 
+    def cbrt(x) -> float:  # type: ignore
+        """math.cbrt was added in Python 3.11"""
+        return x ** (1 / 3)
+
 
 __all__ = ["cart2pol", "pol2cart", "cart2sph", "sph2cart", "sign"]