.. _method-bayes_calibration-muq-delayed_rejection:

"""""""""""""""""
delayed_rejection
"""""""""""""""""


Use the Delayed Rejection MCMC algorithm



**Topics**


bayesian_calibration


.. toctree::
   :hidden:
   :maxdepth: 1

   method-bayes_calibration-muq-delayed_rejection-num_stages
   method-bayes_calibration-muq-delayed_rejection-scale_type
   method-bayes_calibration-muq-delayed_rejection-delay_scale


**Specification**

- *Alias:* None

- *Arguments:* None

- *Default:* dram


**Child Keywords:**

+-------------------------+--------------------+--------------------+-----------------------------------------------+
| Required/Optional       | Description of     | Dakota Keyword     | Dakota Keyword Description                    |
|                         | Group              |                    |                                               |
+=========================+====================+====================+===============================================+
| Optional                                     | `num_stages`__     | Number of stages                              |
+----------------------------------------------+--------------------+-----------------------------------------------+
| Optional                                     | `scale_type`__     | Type of scaling to use                        |
+----------------------------------------------+--------------------+-----------------------------------------------+
| Optional                                     | `delay_scale`__    | Scaling parameter                             |
+----------------------------------------------+--------------------+-----------------------------------------------+

.. __: method-bayes_calibration-muq-delayed_rejection-num_stages.html
__ method-bayes_calibration-muq-delayed_rejection-scale_type.html
__ method-bayes_calibration-muq-delayed_rejection-delay_scale.html



**Description**


This keyword specifies the use of the Delayed Rejection algorithm in
which there can be a delay in rejecting samples from the chain.  That
is, the "DR" part of DRAM is used but the "AM" part is not, rather a
regular Metropolis-Hastings algorithm is used.

*Default Behavior*

Five MCMC algorithm variants are supported: ``dram``,
``delayed_rejection``, ``adaptive_metropolis``, ``metropolis_hastings``, and
``multilevel``.  The default is ``dram``.

*Usage Tips*

If the user knows something about the proposal covariance or the
proposal covariance is informed through derivative information, using
``delayed_rejection`` is preferred over ``dram``: the proposal covariance is
already being informed by derivative information and the adaptive
metropolis is not necessary.



**Examples**



.. code-block::

    method,
            bayes_calibration queso
              delayed_rejection
              samples = 10000 seed = 348