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Dakota Reference Manual
Version 6.15
Explore and Predict with Confidence
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Select a replacement type for SCOLIB evolutionary algorithm (coliny_ea
)
Alias: none
Argument(s): none
Default: elitist=1
Child Keywords:
Required/Optional | Description of Group | Dakota Keyword | Dakota Keyword Description | |
---|---|---|---|---|
Required (Choose One) | Replacement Type (Group 1) | random | Create new population randomly | |
chc | Create new population using replacement | |||
elitist | Use the best designs to form a new population | |||
Optional | new_solutions_generated | Replace population with individuals chosen from population |
The replacement_type controls how current populations and newly generated individuals are combined to create a new population. Each of the replacement_type selections accepts an associated integer value, which is specified by the replacement_size:
The random setting creates a new population using (a) replacement_size
randomly selected individuals from the current population, and (b) population_size
- replacement_size
individuals randomly selected from among the newly generated individuals (the number of which is optionally specified using new_solutions_generated
) that are created for each generation (using the selection, crossover, and mutation procedures).
The chc setting creates a new population using (a) the replacement_size
best individuals from the combination of the current population and the newly generated individuals, and (b) population_size
- replacement_size
individuals randomly selected from among the remaining individuals in this combined pool. The chc setting is the preferred selection for many engineering problems.
The elitist (default) setting creates a new population using (a) the replacement_size
best individuals from the current population, (b) and population_size
- replacement_size
individuals randomly selected from the newly generated individuals. It is possible in this case to lose a good solution from the newly generated individuals if it is not randomly selected for replacement; however, the default new_solutions_generated
value is set such that the entire set of newly generated individuals will be selected for replacement.
Note that new_solutions_generated
is not recognized by Dakota as a valid keyword unless replacement_type
has been specified.