mixed_gradients
Gradients are needed and will be obtained from a mix of numerical and analytic sources
Specification
Alias: None
Arguments: None
Child Keywords:
Required/Optional 
Description of Group 
Dakota Keyword 
Dakota Keyword Description 

Required 
Identify which numerical gradient corresponds to which response 

Required 
Identify which analytical gradient corresponds to which response 

Optional 
Specify which finite difference routine is used 

Optional (Choose One) 
Gradient Source 
(Default) Use internal Dakota finite differences algorithm 

Use nonDakota fd algorithm 

Optional 
Specify how to compute gradients and hessians 

Optional (Choose One) 
Finite Difference Type 
(Default) Use forward differences 

Use central differences 

Optional 
Step size used when computing gradients and Hessians 
Description
The mixed_gradients
specification means that some gradient
information is available directly from the simulation (analytic)
whereas the rest will have to be finite differenced (numerical). This
specification allows the user to make use of as much analytic gradient
information as is available and then finite difference for the
rest.
The method_source
, interval_type
,
and fd_gradient_step_size
specifications
pertain to those functions listed
by the id_numerical_gradients
list.
Examples
For example, the objective function may be a simple analytic function of the design variables (e.g., weight) whereas the constraints are nonlinear implicit functions of complex analyses (e.g., maximum stress).