How do I find the nearest positive definite matrix to a correlation matrix?

Questions
1

Has anyone developed Mathematica code to find the nearest positive definite matrix to a proposed correlation matrix? An investment consultant has published his proposed correlation matrix, but it is not positive definite, and cannot be used for modeling. There are a number of solutions in R and MatLab on the Web. Is there a solution in Mathematica?

Thanks.

2

This post on the Mathematica StackExchange site has an example implementation of two popular methods due to R. Rebonato and P. Jäckel.