import os
from keras.backend.tensorflow_backend import set_session

os.environ["CUDA_VISIBLE_DEVICES"] = "0"
config = tf.ConfigProto()
config.gpu_options.per_process_gpu_memory_fraction = 0.3
set_session(tf.Session(config=config))

import keras.backend.tensorflow_backend as KTF
import os

os.environ["CUDA_VISIBLE_DEVICES"] = "0"
config = tf.ConfigProto()
config.gpu_options.allow_growth=True 
sess = tf.Session(config=config)
KTF.set_session(sess)