`zlauum:`procedureThese routines compute the product

*U * U*' or*L' * L*, where the triangular factor*U*or*L*is stored in the upper or lower triangular part of the array*A*. Argument UPLO indicates whether upper or lower triangle of A is stored (**Upper**or*Lower*'). Optional argument*LDA*is the leading dimension of array*A*. The return value is the lower triangle of the lower triangular product, or the upper triangle of upper triangular product, in the respective storage format.