我有两个随机变量X和Y,它们均匀分布在单纯形上:
我想评估它们的总和的密度:
在评估上述积分之后,我的最终目标是计算以下积分:
为了计算第一个积分,我正在生成单纯形中均匀分布的点,然后检查它们是否属于上述积分中所需的区域,并采用点的分数来评估上述密度。
一旦我计算出上述密度,我将遵循类似的过程来计算上述对数积分以计算其值。然而,这非常低效并且需要很长时间,例如3-4小时。有人能建议我在Python中解决这个问题的有效方法吗?我正在使用Numpy包。
以下是代码:
![simplex](https://istack.dev59.com/GjV1E.gif)
![enter image description here](https://istack.dev59.com/G8QL2.gif)
一旦我计算出上述密度,我将遵循类似的过程来计算上述对数积分以计算其值。然而,这非常低效并且需要很长时间,例如3-4小时。有人能建议我在Python中解决这个问题的有效方法吗?我正在使用Numpy包。
以下是代码:
import numpy as np
import math
import random
import numpy.random as nprnd
import matplotlib.pyplot as plt
from matplotlib.backends.backend_pdf import PdfPages
#This function checks if the point x lies the simplex and the negative simplex shifted by z
def InreqSumSimplex(x,z):
dim=len(x)
testShiftSimpl= all(z[i]-1 <= x[i] <= z[i] for i in range(0,dim)) and (sum(x) >= sum(z)-1)
return int(testShiftSimpl)
def InreqDiffSimplex(x,z):
dim=len(x)
testShiftSimpl= all(z[i] <= x[i] <= z[i]+1 for i in range(0,dim)) and (sum(x) <= sum(z)+1)
return int(testShiftSimpl)
#This is for the density X+Y
def DensityEvalSum(z,UniformCube):
dim=len(z)
Sum=0
for gen in UniformCube:
Exponential=[-math.log(i) for i in gen] #This is exponentially distributed
x=[i/sum(Exponential) for i in Exponential[0:dim]] #x is now uniformly distributed on simplex
Sum+=InreqSumSimplex(x,z)
Sum=Sum/numsample
FunVal=(math.factorial(dim))*Sum;
if FunVal<0.00001:
return 0.0
else:
return -math.log(FunVal)
#This is for the density X-Y
def DensityEvalDiff(z,UniformCube):
dim=len(z)
Sum=0
for gen in UniformCube:
Exponential=[-math.log(i) for i in gen]
x=[i/sum(Exponential) for i in Exponential[0:dim]]
Sum+=InreqDiffSimplex(x,z)
Sum=Sum/numsample
FunVal=(math.factorial(dim))*Sum;
if FunVal<0.00001:
return 0.0
else:
return -math.log(FunVal)
def EntropyRatio(dim):
UniformCube1=np.random.random((numsample,dim+1));
UniformCube2=np.random.random((numsample,dim+1))
IntegralSum=0; IntegralDiff=0
for gen1,gen2 in zip(UniformCube1,UniformCube2):
Expo1=[-math.log(i) for i in gen1]; Expo2=[-math.log(i) for i in gen2]
Sumz=[ (i/sum(Expo1)) + j/sum(Expo2) for i,j in zip(Expo1[0:dim],Expo2[0:dim])] #Sumz is now disbtributed as X+Y
Diffz=[ (i/sum(Expo1)) - j/sum(Expo2) for i,j in zip(Expo1[0:dim],Expo2[0:dim])] #Diffz is now distributed as X-Y
UniformCube=np.random.random((numsample,dim+1))
IntegralSum+=DensityEvalSum(Sumz,UniformCube) ; IntegralDiff+=DensityEvalDiff(Diffz,UniformCube)
IntegralSum= IntegralSum/numsample; IntegralDiff=IntegralDiff/numsample
return ( (IntegralDiff +math.log(math.factorial(dim)))/ ((IntegralSum +math.log(math.factorial(dim)))) )
Maxdim=11
dimlist=range(2,Maxdim)
Ratio=len(dimlist)*[0]
numsample=10000
for i in range(len(dimlist)):
Ratio[i]=EntropyRatio(dimlist[i])
profilehooks
模块来进行分析。 - MaxNoe