Question

我有4个载体：

x1 = [-27.445,-26.960,-26.635,-26.431,-26.315];
x2 = [-25.673,-25.497,-25.449,-25.491,-25.593];
x3 = [-29.310,-28.201,-27.240,-26.399,-25.654];
x4 = [-28.761,-27.103,-26.290,-25.605,-25.025];

我必须随机生成100个向量，但根据x1具有40％权重的概率，x2具有30％，x3具有20％，x4具有10％。

有人可以帮我在matlab中做到这一点吗？提前谢谢。

Answer 1

您就是这样做的：

N=100;
W0=[40,30,20,10]'; %column vec

x1 = [-27.445,-26.960,-26.635,-26.431,-26.315];
x2 = [-25.673,-25.497,-25.449,-25.491,-25.593];
x3 = [-29.310,-28.201,-27.240,-26.399,-25.654];
x4 = [-28.761,-27.103,-26.290,-25.605,-25.025];
X0=cat(1,x1,x2,x3,x4);

assert(size(W0,1)==size(X0,1)) %ensure same size of W and X 

W=W0/sum(W0); %normalize w to be probability vector
S=cumsum(W); % prepare the trick. we going to hit with rand() in range with proability

Rands=rand(1,N);
IsInRange=Rands<S; %for old matlab use: IsInRange=bsxfun(@lt,Rands,S)
[~,I]=max(IsInRange); %find the index

Result=X0(I,:)

如何用matlab生成带加权概率的随机向量

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