Blurb::
Aggregate the variances over all QoIs to generate a target for each level in a MLMC algorithm.
Description::
The variances of the ``allocation_target`` of :math:`Y^i_\ell, i = 1,...,R`  are aggregated and a single sample allocation is computed.
Topics::

Examples::
The following method block

.. code-block::

    method,
     model_pointer = 'HIERARCH'
            multilevel_sampling
       pilot_samples = 20 seed = 1237
       convergence_tolerance = .01
       allocation_target = mean
          qoi_aggregation = sum


uses the sum rule to aggregate the variance over the qois.
Theory::

Faq::

See_Also::
