mixed

Maintain continuous/discrete variable distinction

Specification

• Alias: None

• Arguments: None

• Default: relaxed (branch and bound), mixed (all other methods)

Description

The variables domain specifies how the discrete variables are treated. If the user specifies mixed in the variable specification block, the continuous and discrete variables are treated separately. If the user specifies relaxed in the variable specification block, the discrete variables are relaxed and treated as continuous variables. This may be useful in optimization problems involving both continuous and discrete variables when a user would like to use an optimization method that is designed for continuous variable optimization. All Dakota methods have a default value of mixed for the domain type except for the branch-and-bound method which has a default domain type of relaxed. Note that the branch-and-bound method is under development at this time. Finally, note that the domain selection applies to all variable types: design, aleatory uncertain, epistemic uncertain, and state.

With respect to domain type, if the user does not specify an explicit override of mixed or relaxed, Dakota infers the domain type from the method. As mentioned above, all methods currently use a mixed domain as a default, except the branch-and-bound method which is under development.