Python3: resources and libraries

[csit.git] / resources / libraries / python / PLRsearch / log_plus.py

diff --git a/resources/libraries/python/PLRsearch/log_plus.py b/resources/libraries/python/PLRsearch/log_plus.py
index 1c802a5..62378f6 100644 (file)
--- a/resources/libraries/python/PLRsearch/log_plus.py
+++ b/resources/libraries/python/PLRsearch/log_plus.py
@@ -24,7 +24,7 @@ functions of this module use None as -inf.
 
 TODO: Figure out a more performant way of handling -inf.
 
-The functions handle the common task of adding or substracting
+The functions handle the common task of adding or subtracting
 two numbers where both operands and the result is given in logarithm form.
 There are conditionals to make sure overflow does not happen (if possible)
 during the computation."""
@@ -33,7 +33,7 @@ import math
 
 
 def log_plus(first, second):
-    """Return logarithm of the sum of two exponentials.
+    """Return logarithm of the sum of two exponents.
 
     Basically math.log(math.exp(first) + math.exp(second))
     which avoids overflow and uses None as math.log(0.0).
@@ -47,19 +47,19 @@ def log_plus(first, second):
     :returns: Logarithm of the sum (or None if zero).
     :rtype: float
     """
-
     if first is None:
         return second
     if second is None:
         return first
     if second > first:
-        return second + math.log(1.0 + math.exp(first - second))
+        retval = second + math.log(1.0 + math.exp(first - second))
     else:
-        return first + math.log(1.0 + math.exp(second - first))
+        retval = first + math.log(1.0 + math.exp(second - first))
+    return retval
 
 
 def log_minus(first, second):
-    """Return logarithm of the difference of two exponentials.
+    """Return logarithm of the difference of two exponents.
 
     Basically math.log(math.exp(first) - math.exp(second))
     which avoids overflow and uses None as math.log(0.0).
@@ -75,18 +75,18 @@ def log_minus(first, second):
     :rtype: float
     :raises RuntimeError: If the difference would be non-positive.
     """
-
     if first is None:
-        raise RuntimeError("log_minus: does not suport None first")
+        raise RuntimeError(u"log_minus: does not support None first")
     if second is None:
         return first
     if second >= first:
-        raise RuntimeError("log_minus: first has to be bigger than second")
+        raise RuntimeError(u"log_minus: first has to be bigger than second")
     factor = -math.expm1(second - first)
     if factor <= 0.0:
-        raise RuntimeError("log_minus: non-positive number to log")
+        msg = u"log_minus: non-positive number to log"
     else:
         return first + math.log(factor)
+    raise RuntimeError(msg)
 
 
 def safe_exp(log_value):