我想将随机数放在向量中的第一个gamma A = randi(255,737280,1);
B = randi(255,737280,1);
C = zeros(size(A));
b_vals = unique(B);
for l = 1:numel(b_vals)
b_inds = find(B==b_vals(l)); %// find the indices of each unique value in B
a_inds = find(A==b_vals(l)); %// find the indices of each unique value in A
%// in case the length of a_inds is greater than the length of b_inds
%// duplicate b_inds until it is larger (or equal)
b_inds = repmat(b_inds,[ceil(numel(a_inds)/numel(b_inds)),1]);
%// truncate b_inds to be the same length as a_inds (if necessary) and
%// put b_inds into the proper places in C
C(a_inds) = b_inds(1:numel(a_inds));
end
从另一个向量中的第二个伽玛[gamma with shape=2 , rate=4]
[gamma with shape=3 , rate=4]答案 0 :(得分：0)
你可以尝试（如果我明白你的意思）：
rgamma(20,shape=sample(2:3,20,replace=TRUE,prob=c(0.8,0.2)),rate=4)
shape sample来自2:3，而{2}概率为80％。然后你可以只调用rgamma一次，因为它的矢量化性质。
如果您需要两个不同的向量，您可以：
nShape2<-rbinom(1,20,.80)
vecShape2<-rgamma(nShape2,shape=2,rate=4)
vecShape3<-rgamma(20-nShape2,shape=3,rate=4)