Merge 2f65900 into 3ecf242

spinn_utilities/helpful_functions.py

@@ -16,8 +16,15 @@
 import logging
 import inspect
 import re
+from six.moves import reduce
+import sys
 from six import string_types
 
+if sys.version_info >= (3, 5):
+    from math import gcd as _gcd  # pylint: disable=no-name-in-module
+else:
+    from fractions import gcd as _gcd  # noqa: ignore=W1505
+
 logger = logging.getLogger(__name__)
 FINISHED_FILENAME = "finished"
 
@@ -47,3 +54,54 @@ def is_singleton(value):
         to represent an iterable of characters
     """
     return not hasattr(value, '__iter__') or isinstance(value, string_types)
+
+
+def _lcm(a, b):
+    return (a * b) // _gcd(a, b)  # noqa: ignore=W1505 # pylint: disable=deprecated-method
+
+
+def lcm(*numbers):
+    """
+    Lowest common multiple of 0, 1 or more integers.
+
+    GIGO: If any of the values are anything except positive int values\
+    this function will either produce incorrect results or raise an exception.
+
+    :param numbers: The Positive integers to get the lcm for.\
+    This can be zero, one or more int values or\
+    a singelton which is an iterator (possibly empty) of ints.
+    :return: the lcm or 1 if numbers is empty or an empty iterator
+    :rtype: int
+    :raises TypeError: If any value can not be interpreted as an Integer
+    :raises ZeroDivisionError: May be raised if one of the values is zero
+    """
+    if len(numbers) == 1:
+        try:
+            return reduce(_lcm, iter(numbers[0]), 1)
+        except TypeError:
+            return numbers[0]
+    return reduce(_lcm, numbers, 1)
+
+
+def gcd(*numbers):
+    """
+    Greatest Common Divisor of 1 or more integers.
+
+    GIGO: If any of the values are anything except positive int values\
+    this function will either produce incorrect results or raise an exception.
+
+    :param numbers: The Positive integers to get the lcm for.\
+        This can be one or more int values or\
+        a singelton which is an iterator (not empty) of ints.
+    :return: the lcm or 1 if numbers is empty or an empty iterator
+    :rtype: int
+    :raises TypeError: If any value can not be interpreted as an Integer or\
+        if no value a are provided
+    :raises ZeroDivisionError: May be raised if one of the values is zero
+    """
+    if len(numbers) == 1:
+        try:
+            return reduce(_gcd, iter(numbers[0]))
+        except TypeError:
+            return numbers[0]
+    return reduce(_gcd, numbers)

unittests/test_helpful_functions.py

@@ -15,7 +15,7 @@
 
 import unittests
 from spinn_utilities.helpful_functions import (
-    get_valid_components, is_singleton)
+    get_valid_components, is_singleton, gcd, lcm)
 
 
 def test_is_singleton():
@@ -42,6 +42,32 @@ def test_get_valid_components():
     assert d['b'] == b_c
 
 
+def test_gcd():
+    assert gcd(2) == 2
+    assert gcd(30, 40) == 10
+    assert gcd(120, 40, 60) == 20
+    a = [2, 3, 4]
+    assert gcd(a) == 1
+    b = set([1000, 500, 1500])
+    assert gcd(b) == 500
+    c = [34]
+    assert gcd(c) == 34
+
+
+def test_lcm():
+    assert lcm(2) == 2
+    assert lcm(30, 40) == 120
+    assert lcm(120, 40, 60) == 120
+    assert lcm() == 1
+    assert lcm([]) == 1
+    a = [2, 3, 4]
+    assert lcm(a) == 12
+    b = set([1000, 500, 1500])
+    assert lcm(b) == 3000
+    c = [34]
+    assert lcm(c) == 34
+
+
 # Support class for test_get_valid_components
 class a_b(object):  # noqa: N801
     pass