final int s = species_data.size();
if ( ( ( s * s ) - s ) != ( getN() * 2 ) ) {
throw new IllegalArgumentException( "illegal species count and n: species count:" + s + ", n:" + _n
final int s = species_data.size();
if ( ( ( s * s ) - s ) != ( getN() * 2 ) ) {
throw new IllegalArgumentException( "illegal species count and n: species count:" + s + ", n:" + _n