python 梯度法求解函数极值

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python 梯度法求解函数极值

#coding utf-8
a=0.001             #定义收敛步长
xd=1                #定义寻找步长
x=0                 #定义一个种子x0
i=0                 #循环迭代次数
y=0
dic={}
import math
def f(x):y=math.sin(x)   #定义函数f(X)=sinxreturn y
def fd(x):y=math.cos(x)   #函数f(x)导数fd(X)=cosxreturn y
while y>=0 and y<3.14*4:y=y+xdx=ywhile abs(fd(x))>0.001: #定义精度为0.001x=x+a*fd(x)if x>=0 and x<3.14*4:print(x,f(x))dic[y]=x
print(dic)
ls=[]
for i in dic.keys():cor=0if ls is None:ls.append(dic[i])else:for j in ls:if dic[i]-j<0.1:cor=1breakif cor==0:ls.append(dic[i])
print(ls)