Dakota Reference Manual  Version 6.4
Large-Scale Engineering Optimization and Uncertainty Analysis
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Gradients are needed and will be obtained from a mix of numerical and analytic sources


Alias: none

Argument(s): none

Required/Optional Description of Group Dakota Keyword Dakota Keyword Description
Required id_numerical_gradients Identify which numerical gradient corresponds to which response
Required id_analytic_gradients Identify which analytical gradient corresponds to which response
Optional method_source

Specify which finite difference routine is used

(Choose One)
Group 1 dakota (Default) Use internal Dakota finite differences algorithm
vendor Use non-Dakota fd algorithm
Optional interval_type

Specify how to compute gradients and hessians

(Choose One)
Group 2 forward

(Default) Use forward differences

central Use central differences
Optional fd_step_size

Step size used when computing gradients and Hessians


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.


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).

See Also

These keywords may also be of interest: