void write(final ObjectOutput out) throws IOException {
		out.writeObject(survivorsSelector());
		out.writeObject(offspringSelector());
		out.writeObject(alterer());
		writeInt(populationSize(), out);
		out.writeDouble(offspringFraction());
		writeLong(maximalPhenotypeAge(), out);
	}
Return the number of survivors. <em>This is a derived property.</em>

@return the number of survivors
jenetics/src/main/java/io/jenetics/engine/EvolutionParams.java