.. _model-surrogate-global-gaussian_process-surfpack-optimization_method:

"""""""""""""""""""
optimization_method
"""""""""""""""""""


Change the optimization method used to compute hyperparameters


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



**Specification**

- *Alias:* None

- *Arguments:* STRING

- *Default:* global


**Description**


Select the optimization method to compute hyperparameters of the
Gaussian Process by specifying one of these arguments:


- ``global`` (default) - DIRECT method


- ``local`` - CONMIN method


- ``sampling`` - generates several random guesses and picks the candidate with greatest likelihood


- ``none`` - no optimization, pick the center of the feasible region



The ``none`` option, and the starting location of the
``local`` optimization, default to the center, in
log(correlation length) scale, of the of feasible region.

Surfpack picks a small feasible region of correlation parameters.

Note that we have found the ``global``
optimization method to be the most robust.


