sample.cs: Sample cs
In drvalle1/EcoCluster: Bayesian Clustering using Truncated Stick-Breaking priors

This function generates samples of the group assignment variable cs

sample.cs(
  ngroups,
  omega,
  xmat,
  alpha,
  betas,
  theta,
  nspp,
  nloc,
  InvSigma.precalc,
  Sigma.precalc,
  lds,
  cs,
  nparam
)

`ngroups`	maximum number of species groups (KS)
`omega`	a matrix L x S containing the underlying latent variables omega
`xmat`	the design matrix of dimension L x P
`alpha`	vector of size S with intercept for each species
`betas`	P x KS matrix containing slope parameters for each covariate (row) and each group (column)
`theta`	vector of size KS with the probability of each species group
`nspp`	overall number of species (S)
`nloc`	overall number of locations (L)
`Sigma.precalc`	covariance matrix for new group
`lds`	log of determinant of covariance matrix for new group
`cs`	vector of size S with group assignment for each species
`nparam`	overall number of covariates (P)
`invSigma.precalc`	precision matrix for new group