Python 分类感知器的实现
我已经从开始用Python编写了Percentron示例 这是完整的代码Python 分类感知器的实现,python,neural-network,perceptron,Python,Neural Network,Perceptron,我已经从开始用Python编写了Percentron示例 这是完整的代码 import matplotlib.pyplot as plt import random as rnd import matplotlib.animation as animation NUM_POINTS = 5 LEANING_RATE=0.1 fig = plt.figure() # an empty figure with no axes ax1 = fig.add_subplot(1,1,1) plt.x
import matplotlib.pyplot as plt
import random as rnd
import matplotlib.animation as animation
NUM_POINTS = 5
LEANING_RATE=0.1
fig = plt.figure() # an empty figure with no axes
ax1 = fig.add_subplot(1,1,1)
plt.xlim(0, 120)
plt.ylim(0, 120)
points = []
weights = [rnd.uniform(-1,1),rnd.uniform(-1,1),rnd.uniform(-1,1)]
circles = []
plt.plot([x for x in range(100)], [x for x in range(100)])
for i in range(NUM_POINTS):
x = rnd.uniform(1, 100)
y = rnd.uniform(1, 100)
circ = plt.Circle((x, y), radius=1, fill=False, color='g')
ax1.add_patch(circ)
points.append((x,y,1))
circles.append(circ)
def activation(val):
if val >= 0:
return 1
else:
return -1;
def guess(pt):
vsum = 0
#x and y and bias weights
vsum = vsum + pt[0] * weights[0]
vsum = vsum + pt[1] * weights[1]
vsum = vsum + pt[2] * weights[2]
gs = activation(vsum)
return gs;
def animate(i):
for i in range(NUM_POINTS):
pt = points[i]
if pt[0] > pt[1]:
target = 1
else:
target = -1
gs = guess(pt)
error = target - gs
if target == gs:
circles[i].set_color('r')
else:
circles[i].set_color('b')
#adjust weights
weights[0] = weights[0] + (pt[0] * error * LEANING_RATE)
weights[1] = weights[1] + (pt[1] * error * LEANING_RATE)
weights[2] = weights[2] + (pt[2] * error * LEANING_RATE)
ani = animation.FuncAnimation(fig, animate, interval=1000)
plt.show()
我希望绘制在图形上的点根据预期条件(x坐标>y坐标)将自己分类为红色或蓝色,即参考线(y=x)上方或下方
这似乎不起作用,经过一些迭代后,所有点都变红
我做错了什么。youtube的例子也是如此。我看了你的代码和视频,我相信你的代码是以绿色开头的,如果他们的猜测与目标相符,他们会变为红色,如果他们的猜测与目标不符,他们会变为蓝色。当他们的猜测与目标匹配时,剩余的蓝色最终变为红色。(不断变化的权重可能会将红色变为蓝色,但最终会得到纠正。) 下面是我对代码的修改,它通过以下方式减慢了过程:添加更多的点;每帧仅处理一个点,而不是所有点:
import random as rnd
import matplotlib.pyplot as plt
import matplotlib.animation as animation
NUM_POINTS = 100
LEARNING_RATE = 0.1
X, Y = 0, 1
fig = plt.figure() # an empty figure with no axes
ax1 = fig.add_subplot(1, 1, 1)
plt.xlim(0, 120)
plt.ylim(0, 120)
plt.plot([x for x in range(100)], [y for y in range(100)])
weights = [rnd.uniform(-1, 1), rnd.uniform(-1, 1)]
points = []
circles = []
for i in range(NUM_POINTS):
x = rnd.uniform(1, 100)
y = rnd.uniform(1, 100)
points.append((x, y))
circle = plt.Circle((x, y), radius=1, fill=False, color='g')
circles.append(circle)
ax1.add_patch(circle)
def activation(val):
if val >= 0:
return 1
return -1
def guess(point):
vsum = 0
# x and y and bias weights
vsum += point[X] * weights[X]
vsum += point[Y] * weights[Y]
return activation(vsum)
def train(point, error):
# adjust weights
weights[X] += point[X] * error * LEARNING_RATE
weights[Y] += point[Y] * error * LEARNING_RATE
point_index = 0
def animate(frame):
global point_index
point = points[point_index]
if point[X] > point[Y]:
answer = 1 # group A (X > Y)
else:
answer = -1 # group B (Y > X)
guessed = guess(point)
if answer == guessed:
circles[point_index].set_color('r')
else:
circles[point_index].set_color('b')
train(point, answer - guessed)
point_index = (point_index + 1) % NUM_POINTS
ani = animation.FuncAnimation(fig, animate, interval=100)
plt.show()
我抛出了特殊的0,0输入修复,因为它不适用于本例
底线是,如果一切正常,它们都应该变成红色。如果希望颜色反映分类,则可以更改此条款:
if answer == guessed:
circles[point_index].set_color('r' if answer == 1 else 'b')
else:
circles[point_index].set_color('g')
train(point, answer - guessed)
谢谢……这很有帮助。我对神经网络还是新手。你能给我举个例子,让我的神经网络知识从现在的位置得到提升吗?对不起,@rahulttare,我刚刚看了视频并增强了代码——我对神经网络一无所知。我希望其他人在阅读这篇文章时能给你一些例子。