keras/examples/mnist_mlp.py

from __future__ import absolute_import
from __future__ import print_function
import numpy as np
np.random.seed(1337)  # for reproducibility

from keras.datasets import mnist
from keras.models import Sequential
from keras.layers.core import Dense, Dropout, Activation
from keras.optimizers import SGD, Adam, RMSprop
from keras.utils import np_utils

'''
    Train a simple deep NN on the MNIST dataset.

    Get 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.
'''

batch_size = 128
nb_classes = 10
nb_epoch = 20

# the data, shuffled and split between tran 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')

# convert class vectors to binary class matrices
Y_train = np_utils.to_categorical(y_train, nb_classes)
Y_test = np_utils.to_categorical(y_test, nb_classes)

model = Sequential()
model.add(Dense(512, input_shape=(784,)))
model.add(Activation('relu'))
model.add(Dropout(0.2))
model.add(Dense(512))
model.add(Activation('relu'))
model.add(Dropout(0.2))
model.add(Dense(10))
model.add(Activation('softmax'))

rms = RMSprop()
model.compile(loss='categorical_crossentropy', optimizer=rms)

model.fit(X_train, Y_train,
          batch_size=batch_size, nb_epoch=nb_epoch,
          show_accuracy=True, verbose=2,
          validation_data=(X_test, Y_test))
score = model.evaluate(X_test, Y_test,
                       show_accuracy=True, verbose=0)
print('Test score:', score[0])
print('Test accuracy:', score[1])