[英]How to approximate a value from a formula
So I have one vector of alpha, one vector of beta, and I am trying to find a theta for when the sum of all the estimates (for alpha's 1 to N
and beta's 1 to N
) equals 60: 所以我有一个alpha矢量,一个beta矢量,我试图找到一个theta,当所有估计的总和(对于alpha的1 to N
和beta的1 to N
)等于60:
def CalcTheta(grensscore, alpha, beta):
theta = 0.0001
estimate = [grensscore-1]
while(sum(estimate) < grensscore):
theta += 0.00001
for x in range(len(beta)):
if x == 0:
estimate = []
estimate.append(math.exp(alpha[x] * (theta - beta[x])) /
(1 + math.exp(alpha[x] * (theta - beta[x]))))
return(theta)
Basically what I did is start from theta = 0.0001
, and iterate through, calculating all these sums, and when it is lower than 60, continue by adding 0.0001 each time, while above 60 means we found the theta. 基本上我所做的是从theta = 0.0001
开始,并迭代计算所有这些总和,当它低于60时,继续每次加0.0001,而高于60意味着我们找到了theta。
I found the value theta
this way. 我找到的值theta
这种方式。 Problem is, it took me about 60 seconds using Python, to find a theta of 0.456. 问题是,使用Python花了大约60秒来找到0.456的θ。
What is quicker approach to find this theta (since I would like to apply this for other data)? 什么是更快找到这个theta的方法(因为我想将其应用于其他数据)?
如果你知道θ的下限和上限,并且函数在它们之间的范围内是单调的,那么你可以使用二分算法来轻松快速地找到所需的值。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.