JuliaLang/julia — pull request #1663 by daviddelaat (2012-12-03 20:14:59+00:00)
Title: Check whether a matrix is positive definite.

It uses the LAPACK potrf function, which is (as far as I know) the preferred way to check whether a matrix is positive definite.

When the second argument is true (false), it only uses the upper (lower) diagonal part. When no second argument is provided it first checks whether the matrix is hermitian.