版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/github_39611196/article/details/83117346
代码:
from functools import reduce
class Perceptron(object):
def __init__(self, input_num, activator):
'''
初始化感知器,设置输输入参数的个数以及激活函数
:param input_num:
:param activator:
'''
self.activator = activator
# 权重向量初始化为0
self.weights = [0.0 for _ in range(input_num)]
# 初始化偏置项为0
self.bias = 0
def __str__(self):
'''
打印学习到的权重、偏置项
:return:
'''
return 'weights\t:%s\nbias\t:%f\n' % (self.weights, self.bias)
def predict(self, input_vec):
'''
输入向量,输出感知器的计算结果
:param input_vec:
:return:
'''
# 把input_vec[x1, x2,x3...]和weights[w1, w2, w3..]打包在一起
# 变成[(x1, w1), (x2, w2), (x3, w3),..]
# 然后利用map函数计算[x1*w1, x2*w2, x3* w3]
# 最后利用reduce求和
return self.activator(
reduce(lambda a, b: a + b,
[x * w for x, w in zip(input_vec, self.weights)],
0.0) + self.bias)
def train(self, input_vecs, labels, iteration, rate):
'''
输入训练数据:一组向量、与每个向量对应的label,以及训练轮数、学习率
:param input_vec:
:param labels:
:param iteration:
:param rate:
:return:
'''
for i in range(iteration):
self._one_iteration(input_vecs, labels, rate)
def _one_iteration(self, input_vecs, labels, rate):
'''
一次迭代, 把所有的训练数据过一遍
:param input_vecs:
:param labels:
:param rate:
:return:
'''
# 把输入和输出打包在一起,成为样本的列表[(input_vec, label),..]
# 每个训练样本是(input_vec, label)
samples = zip(input_vecs, labels)
# 对每个样本,按照感知器规则更新权重
for (input_vec, label) in samples:
# 计算服务器在当前权重下的输出
output = self.predict(input_vec)
# 更新权重
self._update_weights(input_vec, output, label, rate)
def _update_weights(self, input_vec, output, label, rate):
'''
按照感知器啊规则更新权重
:param input_vec:
:param output:
:param label:
:param rate:
:return:
'''
# 把input_vec[x1,x2,x3,...]和weights[w1,w2,w3,...]打包在一起
# 变成[(x1,w1),(x2,w2),(x3,w3),...]
# 然后利用感知器规则更新权重
delta = label - output
self.weights = [ w + rate * delta * x
for x, w in zip(input_vec, self.weights)]
# 更新权重
self.bias += rate * delta
# 定义激活函数
f = lambda x: x
# 定义线性单元
class LinearUnit(Perceptron):
def __init__(self, input_num):
'''
初始化线性单元,设置输入参数的个数
:param input_num:
'''
Perceptron.__init__(self, input_num, f)
# 构造数据
def get_training_dataset():
'''
捏造5个人的数据
:return:
'''
# 构建向量列表,每一项是供工作年限
input_vecs = [[5], [3], [8], [1.4], [10.1]]
# 期望的输出列表,月薪,主要要与输入一一对应
labels = [5500, 2300, 7600, 1800, 11400]
return input_vecs, labels
def train_linear_unit():
'''
使用数据训练线性单元
:return:
'''
# 创建感知器,输入参数的特征数为1(工作年限)
lu = LinearUnit(1)
# 训练,迭代10轮,学习速率为0.01
input_vecs, labels = get_training_dataset()
lu.train(input_vecs, labels, 10, 0.01)
# 返回训练好的线性单元
return lu
if __name__ == '__main__':
'''训练线性单元'''
linear_unit = train_linear_unit()
# 打印训练获得的权重
print(linear_unit)
# 测试
print(
'Work 3.4 years, monthly salary = %.2f' % linear_unit.predict([3.4]))
print(
'Work 15 years, monthly salary = %.2f' % linear_unit.predict([15]))
print(
'Work 1.5 years, monthly salary = %.2f' % linear_unit.predict([1.5]))
print(
'Work 6.3 years, monthly salary = %.2f' % linear_unit.predict([6.3]))
输出结果:
weights :[1124.0634970262222]
bias :85.485289
Work 3.4 years, monthly salary = 3907.30
Work 15 years, monthly salary = 16946.44
Work 1.5 years, monthly salary = 1771.58
Work 6.3 years, monthly salary = 7167.09