import numpy as np

# the type of float to use throughout the session.
_FLOATX = 'float32'
_EPSILON = 10e-8


def epsilon():
    return _EPSILON


def set_epsilon(e):
    global _EPSILON
    _EPSILON = e


def floatx():
    return _FLOATX


def set_floatx(floatx):
    global _FLOATX
    if floatx not in {'float32', 'float64'}:
        raise Exception('Unknown floatx type: ' + str(floatx))
    floatx = floatx.encode('ascii')
    _FLOATX = floatx


def cast_to_floatx(x):
    '''Cast a Numpy array to floatx.
    '''
    return np.asarray(x, dtype=_FLOATX)

import numpy as np

# the type of float to use throughout the session.
_FLOATX = 'float32'
_EPSILON = 10e-8


def epsilon():
    return _EPSILON


def set_epsilon(e):
    global _EPSILON
    _EPSILON = e


def floatx():
    return _FLOATX


def set_floatx(floatx):
    global _FLOATX
    if floatx not in {'float32', 'float64'}:
        raise Exception('Unknown floatx type: ' + str(floatx))
    if isinstance(floatx, unicode):
        floatx = floatx.encode('ascii')
    _FLOATX = floatx


def cast_to_floatx(x):
    '''Cast a Numpy array to floatx.
    '''
    return np.asarray(x, dtype=_FLOATX)

--- 
+++ 
@@ -22,8 +22,7 @@
     global _FLOATX
     if floatx not in {'float32', 'float64'}:
         raise Exception('Unknown floatx type: ' + str(floatx))
-    if isinstance(floatx, unicode):
-        floatx = floatx.encode('ascii')
+    floatx = floatx.encode('ascii')
     _FLOATX = floatx
 
 
Fix floatx encoding on Python3