avoid Adjoint wrapper for chol_lower(::Matrix)

Author: st--

src/chol.jl

@@ -5,7 +5,8 @@ CholType{T,S<:AbstractMatrix} = Cholesky{T,S}
 chol_lower(a::CholType) = a.uplo === 'L' ? a.L : a.U'
 chol_upper(a::CholType) = a.uplo === 'U' ? a.U : a.L'
 
-chol_lower(a::Matrix) = chol_lower(cholesky(a))
+# For a dense Matrix, the following allows us to avoid the Adjoint wrapper:
+chol_lower(a::Matrix) = cholesky(Hermitian(a, :L)).L
 
 if HAVE_CHOLMOD
     CholTypeSparse{T} = SuiteSparse.CHOLMOD.Factor{T}