@Override
	public Codec<Tree<Op<T>, ?>, ProgramGene<T>> codec() {
		return _codec;
	}
Create a new <em>symbolic</em> regression problem with the given data.

@param codec the codec used for the problem
@param error the error function
@param sampling the sample values used for finding a regression.
jenetics.prog/src/main/java/io/jenetics/prog/regression/Regression.java