mnist数据的预测结果以及批量处理

import sys, os

sys.path.append('F:\ml\DL\source-code')

from dataset.mnist import load_mnist

from PIL import Image

import numpy as np

#pickle提供了一个简单的持久化功能。可以将对象以文件的形式存放在磁盘上。

#pickle模块只能在python中使用，python中几乎所有的数据类型（列表，字典，集合，类等）都可以用pickle来序列化，

#pickle序列化后的数据，可读性差，人一般无法识别。

import pickle

def sigmoid(x):

    return 1 / (1 + np.exp(-x))

def softmax(x):

    m = np.max(x)

    return np.exp(x- m) / np.sum(np.exp(x - m))

def get_data():

    (x_train, t_train), (x_test, t_test) = load_mnist(normalize = True, flatten = True, one_hot_label = False)

    return x_test, t_test

def init_network():

    with open("F:\\ml\DL\\source-code\\ch03\\sample_weight.pkl", 'rb') as f:

        network = pickle.load(f)

    return network

def predict(network, x):

    W1, W2, W3 = network['W1'], network['W2'], network['W3']

    b1, b2, b3 = network['b1'], network['b2'], network['b3']

    a1 = np.dot(x, W1) + b1

    z1 = sigmoid(a1)

    a2 = np.dot(a1, W2) + b2

    z2 = sigmoid(a2)

    a3 = np.dot(z2, W3) + b3

    y = softmax(a3)

    return y

x, t = get_data()

network = init_network()

accuracy_cnt = 0

for i in range(len(x)):

    y = predict(network, x[i])

    p = np.argmax(y)

    if p == t[i]:

        accuracy_cnt += 1

print("Accuracy:" + str(float(accuracy_cnt) / len(x)))

Accuracy:0.8453

#批处理显示

x, t = get_data()

network = init_network()

batch_size = 100

accuracy_cnt = 0

for i in range(0, len(x), batch_size):

    x_batch = x[i:i+batch_size]

    y_batch = predict(network, x_batch)

    p = np.argmax(y_batch, axis = 1)

    accuracy_cnt += np.sum(p == t[i : i+batch_size])

print("Accuracy:" + str(float(accuracy_cnt) / len(x)))

Accuracy:0.8453