Blurb::Specifies the diagonal matrix format when importing a
user-specified proposal covariance.

Description::

When importing the MCMC proposal covariance from a user-specified
filename, this keyword declares the use of a diagonal matrix format,
i.e., the user only provides the (positive) values along the diagonal.

Topics::

Examples::
\verbatim
method,									
        bayes_calibration queso
         samples = 1000 seed = 348
          dram
          proposal_covariance
            diagonal filename 'dakota_cantilever_queso.diag.dat'
\endverbatim

Theory::
Faq::
See_Also::
