private EvolutionStart<G, C>
	evolutionStart(final EvolutionInit<G> init) {
		final ISeq<Genotype<G>> pop = init.population();
		final long gen = init.generation();

		return evolutionStart(
			EvolutionStart.of(
				pop.map(gt -> Phenotype.of(gt, gen)),
				gen
			)
		);
	}
Evaluates the fitness function of the given population with the configured
{@link Evaluator} of this engine and returns a new population
with its fitness value assigned.

@since 5.0

@see Evaluator
@see Evaluator#eval(Seq)

@param population the population to evaluate
@return a new population with assigned fitness values
@throws IllegalStateException if the configured fitness function doesn't
        return a population with the same size as the input population.
        This exception is also thrown if one of the populations
        phenotype has no fitness value assigned.
jenetics/src/main/java/io/jenetics/engine/Engine.java