‘‘‘Trains?a?simple?deep?NN?on?the?MNIST?dataset.

Gets?to?98.40%?test?accuracy?after?20?epochs
（there?is?*a?lot*?of?margin?for?parameter?tuning）.
2?seconds?per?epoch?on?a?K520?GPU.
‘‘‘

from?__future__?import?print_function

import?keras
from?keras.datasets?import?mnist
from?keras.models?import?Sequential
from?keras.layers?import?Dense?Dropout
from?keras.optimizers?import?RMSprop

batch_size?=?128
num_classes?=?10
epochs?=?20

#?the?data?shuffled?and?split?between?train?and?test?sets
（x_train?y_train）?（x_test?y_test）?=?mnist.load_data（）

x_train?=?x_train.reshape（60000?784）
x_test?=?x_test.reshape（10000?784）
x_train?=?x_train.astype（‘float32‘）
x_test?=?x_test.astype（‘float32‘）
x_train?/=?255
x_test?/=?255
print（x_train.shape[0]?‘train?samples‘）
print（x_test.shape[0]?‘test?samples‘