public void propagateBackNN() throws IOException{
		double sum = 0;
		constructNet(head);
		do{
			sum=0;
			Elem tek=head;
			while(tek!=null){
				updateIO(tek);
				Activation();
				Deltas();
				Weights();
				printIO();
				sum += updateError();
				tek=tek.sled;
			}
			//System.out.print("Error: "+sum+"\n");
			if(pom==sum) 
				{ System.out.print("Best I can do to match error is "+pom+", you could try different architecture."); break;}
			pom=sum;
		}
		while (sum>error_tolerance);
		System.out.print("Error: "+sum);
	}