public double calculateSSE(double[] weight) {
		double sse = 0;
		for(Instance instance : mInstances){
			double[] feature = instance.getFeatures();
			double u = DoubleOperation.multiply(feature, weight);
			double label = instance.getLabel();
			sse += (label - u) * (label - u);		
		}
		return sse / 2;
	}