Fix Python 3 compatibility issues

privacy/analysis/rdp_accountant.py

@@ -46,6 +46,11 @@ import sys
 import numpy as np
 from scipy import special
 
+try:
+  long
+except NameError:
+  long = int
+
 ########################
 # LOG-SPACE ARITHMETIC #
 ########################

privacy/optimizers/dp_optimizer_test.py

@@ -24,6 +24,11 @@ import tensorflow as tf
 
 from privacy.optimizers import dp_optimizer
 
+try:
+    xrange
+except NameError:
+    xrange = range
+
 
 def loss(val0, val1):
   """Loss function that is minimized at the mean of the input points."""

privacy/optimizers/gaussian_query_test.py

@@ -24,6 +24,11 @@ import tensorflow as tf
 
 from privacy.optimizers import gaussian_query
 
+try:
+    xrange
+except NameError:
+    xrange = range
+
 
 def _run_query(query, records):
   """Executes query on the given set of records as a single sample.

privacy/optimizers/nested_query_test.py

@@ -30,6 +30,11 @@ nest = tf.contrib.framework.nest
 
 _basic_query = gaussian_query.GaussianSumQuery(1.0, 0.0)
 
+try:
+    xrange
+except NameError:
+    xrange = range
+
 
 def _run_query(query, records):
   """Executes query on the given set of records as a single sample.