an object of type "portfolio" specifying the constraints for the optimization, see portfolio.spec
permutations
integer: number of unique constrained random portfolios to generate
max_permutations
integer: maximum number of iterations to try for a valid portfolio, default 200
Value
a matrix of random portfolio weights
Details
The 'sample' method to generate random portfolios is based
on an idea pioneerd by Pat Burns. This is the most flexible method, but also
the slowest, and can generate portfolios to satisfy leverage, box, group,
and position limit constraints.