// $Id$
//
//    File: nnann_function_step.h
// Created: Thu Apr  7 14:22:02 EDT 2011
// Creator: davidl (on Darwin Amelia.local 9.8.0 i386)
//

#ifndef _nnann_function_step_
#define _nnann_function_step_

#include <cmath>
#include <nnann_function.h>

class nnann_function_step:public nnann_function{
	public:
		nnann_function_step(void){}
		virtual ~nnann_function_step(){};

		std::string GetName(void){return "Step";}

		virtual double f(double x){
			return x>0.5 ? 1.0:0.0;
		}

		virtual double dfdx(double x){
			double xx = x-0.5;
			double slope = fabs(xx)<1.0E-3 ? 1.0E3:(1.0/fabs(xx));
			return xx>0.0 ? slope:-slope; // derivative of step
		}
		
		double InputError(double x, double target){
			double output = f(x);
//_DBG_<<"x="<<x<<" target="<<target<<" output="<<output<<std::endl;
			if(output==target)return 0.0;
			if(output>target)return 0.5-x -0.1;
			return 0.5-x + 0.1;
		}

	protected:
		

};

#endif // _nnann_function_step_