`zpotrf:`procedureThese routines compute the Cholesky factorization of a symmetric positive definite matrix

*A*. The factorization has the form:*A = U**T * U*if UPLO =**Upper***A = L * L**T*if UPLO =**Lower**where*U*is an upper triangular, and*L*is a lower triangular matrix. Optional argument*LDA*is the leading dimension of array*A*. The return value is the factor*U*or*L*from the Cholesky factorization, depending on the value of argument UPLO.