Add docstrings to util.isclose and util.iszero

1 files changed, 12 insertions, 1 deletions

diff --git a/mdpoly/util.py b/mdpoly/util.py
index ed7c234..937e7d4 100644
--- a/mdpoly/util.py
+++ b/mdpoly/util.py
@@ -1,7 +1,6 @@
 from .constants import NUMERICS_EPS
 
 from itertools import tee, filterfalse
-from math import abs
 
 def partition(pred, iterable):
     """Partition entries into false entries and true entries.
@@ -14,8 +13,20 @@ def partition(pred, iterable):
 
 
 def isclose(x: float, y: float, eps: float =NUMERICS_EPS) -> bool:
+    r""" Check if two numbers are close.
+
+    Close means :math:`|x - y| < \varepsilon` where :math:`\varepsilon` is the
+    given ``eps`` or the default value at
+    :py:data:`mdpoly.constants.NUMERICS_EPS`.
+    """
+    # TODO: probably faster with math.isclose
     return abs(x - y) < eps
 
 
 def iszero(x: float, eps: float =NUMERICS_EPS) -> bool:
+    r""" Check a number is zero.
+
+    Being zero means :math:`|x| < \varepsilon` where :math:`\varepsilon` is the given
+    ``eps`` or the default value at :py:data:`mdpoly.constants.NUMERICS_EPS`.
+    """
     return isclose(x, 0.)