compute.r: Sample sizes of mixture proportion groups.
In tpgarcia/stride: STRIDE: Robust powerful mixture models

Computes the number of individuals in each mixture proportion group.

1	compute.r(n, m, p, qvs, q.use)

`n`	sample size, must be at least 1.
`m`	number of different mixture proportions, must be at least 2.
`p`	number of populations, must be at least 2.
`qvs`	a numeric matrix of size `p` by `m` containing all possible mixture proportions (i.e., the probability of belonging to each population k, k=1,...,p.).
`q.use`	a numeric matrix of size `p` by `n` containing the mixture proportions for each person in the sample.