.. _method-nlssol_sqp-verify_level:

""""""""""""
verify_level
""""""""""""


Verify the quality of analytic gradients


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



**Specification**

- *Alias:* None

- *Arguments:* INTEGER

- *Default:* -1 (no gradient verification)


**Description**


``verify_level`` instructs the NPSOL and NLSSOL algorithms to perform
their own finite difference verification of the gradients provided by
Dakota.  Typically these are used to verify ``analytic_gradients``
produced by a simulation code, though the option can be used with
other Dakota-supplied gradient types including numerical or mixed.

Level 1 will verify the objective gradients, level 2, the nonlinear
constraint gradients, and level 3, both.  See the Optional Input
Parameters section of the NPSOL manual  :cite:p:`Gil86` for additional
information, including options to verify at the user-supplied initial
point vs. first feasible point.