import tensorflow as tf
from sklearn.datasets import load_digits
#from sklearn.cross_validation import train_test_split
from sklearn.model_selection import train_test_split
from sklearn.preprocessing import LabelBinarizer

# load data
digits = load_digits()  X = digits.data
y = digits.target
y = LabelBinarizer().fit_transform(y)  
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=.3)


 
def add_layer(inputs, in_size, out_size, layer_name, activation_function=None, ):
    # add one more layer and return the output of this layer
    Weights = tf.Variable(tf.random_normal([in_size, out_size]))
    biases = tf.Variable(tf.zeros([1, out_size]) + 0.1, )
    Wx_plus_b = tf.matmul(inputs, Weights) + biases
    
 
# here to dropout
    Wx_plus_b = tf.nn.dropout(Wx_plus_b, keep_prob)  
    if activation_function is None:
        outputs = Wx_plus_b
    else:
        outputs = activation_function(Wx_plus_b, )
    tf.summary.histogram(layer_name + '/outputs', outputs) 
    return outputs


# define placeholder for inputs to network
 

keep_prob = tf.placeholder(tf.float32)      
xs = tf.placeholder(tf.float32, [None, 64])  
ys = tf.placeholder(tf.float32, [None, 10])

# add output layer
l1 = add_layer(xs, 64, 50, 'l1', activation_function=tf.nn.tanh)            
prediction = add_layer(l1, 50, 10, 'l2', activation_function=tf.nn.softmax) 

# the loss between prediction and real data
cross_entropy = tf.reduce_mean(-tf.reduce_sum(ys * tf.log(prediction),
                                              reduction_indices=[1]))  
tf.summary.scalar ('loss', cross_entropy)  
train_step = tf.train.GradientDescentOptimizer(0.5).minimize(cross_entropy) 

sess = tf.Session()
merged =  tf.summary.merge_all()    
# summary writer goes in here
train_writer = tf.summary.FileWriter("logs4/train", sess.graph)  
test_writer = tf.summary.FileWriter("logs4/test", sess.graph)    

sess.run(tf.global_variables_initializer()) 

for i in range(500):  
    # here to determine the keeping probability
    sess.run(train_step, feed_dict={xs: X_train, ys: y_train, keep_prob: 0.5})  
    if i % 50 == 0:
        # record loss
        train_result = sess.run(merged, feed_dict={xs: X_train, ys: y_train, keep_prob: 1})
        test_result = sess.run(merged, feed_dict={xs: X_test, ys: y_test, keep_prob: 1})
        train_writer.add_summary(train_result, i)  
        test_writer.add_summary(test_result, i)