replacement_type
Select a replacement type for SCOLIB evolutionary algorithm ( coliny_ea)
Specification
Alias: None
Arguments: None
Default: elitist=1
Child Keywords:
Required/Optional |
Description of Group |
Dakota Keyword |
Dakota Keyword Description |
|---|---|---|---|
Required (Choose One) |
Replacement Type |
Create new population randomly |
|
Create new population using replacement |
|||
Use the best designs to form a new population |
|||
Optional |
Replace population with individuals chosen from population |
||
Description
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.
