.. _responses-numerical_gradients:

"""""""""""""""""""
numerical_gradients
"""""""""""""""""""


Gradients are needed and will be approximated by finite differences


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

   responses-numerical_gradients-method_source
   responses-numerical_gradients-interval_type
   responses-numerical_gradients-fd_step_size


**Specification**

- *Alias:* None

- *Arguments:* None


**Child Keywords:**

+-------------------------+--------------------+--------------------+-----------------------------------------------+
| Required/Optional       | Description of     | Dakota Keyword     | Dakota Keyword Description                    |
|                         | Group              |                    |                                               |
+=========================+====================+====================+===============================================+
| Optional                                     | `method_source`__  | Specify which finite difference routine is    |
|                                              |                    | used                                          |
+----------------------------------------------+--------------------+-----------------------------------------------+
| Optional                                     | `interval_type`__  | Specify how to compute gradients and hessians |
+----------------------------------------------+--------------------+-----------------------------------------------+
| Optional                                     | `fd_step_size`__   | Step size used when computing gradients and   |
|                                              |                    | Hessians                                      |
+----------------------------------------------+--------------------+-----------------------------------------------+

.. __: responses-numerical_gradients-method_source.html
__ responses-numerical_gradients-interval_type.html
__ responses-numerical_gradients-fd_step_size.html



**Description**


The ``numerical_gradients`` specification means that gradient
information is needed and will be computed with finite differences
using either the native or one of the vendor finite differencing
routines.