public class ExpCommStrength implements ICommStrengthFunc {

	double m_lfCutoff;
	double m_lfDecay;
	
	public ExpCommStrength() {
		m_lfCutoff = 1.0;
		m_lfDecay = 1.0;
	}
	
	public ExpCommStrength(double lfCutoff, double lfDecay) {
		m_lfCutoff = lfCutoff;
		m_lfDecay = lfDecay;
	}
	
	public ExpCommStrength(ExpCommStrength src) {
		m_lfCutoff = src.m_lfCutoff;
		m_lfDecay = src.m_lfDecay;
	}
	
	public void setVars(double lfCutoff, double lfDecay) {
		m_lfCutoff = lfCutoff;
		m_lfDecay = lfDecay;
	}
	
	public double getStrength(double lfDist) {
		
		if(lfDist < m_lfCutoff) {
			return 1.0;
		}
		return Math.exp(m_lfDecay*(m_lfCutoff - lfDist));
	}

	public double getGrad(double lfDist) {
		if(lfDist < m_lfCutoff) {
			return 0.0;
		}
		return -m_lfDecay*Math.exp(m_lfDecay*(m_lfCutoff - lfDist));
	}
	
	public double maxStrengthRange(double lfMinD, double lfMaxD)
	{
		if(lfMinD < m_lfCutoff) {
			return 1.0;
		}
		return Math.exp(m_lfDecay*(m_lfCutoff - lfMinD));
	}
	
	public double minStrengthRange(double lfMinD, double lfMaxD)
	{
		if(lfMaxD < m_lfCutoff) {
			return 1.0;
		}
		return Math.exp(m_lfDecay*(m_lfCutoff - lfMaxD));
	}

	public boolean isMonotonic() {
		return true;
	}
	
	public double minDerivRange(double lfMin, double lfMax)
	{
		if(lfMin < m_lfCutoff) {
			if(lfMax < m_lfCutoff) {
				return 0.0;
			}
			lfMin = m_lfCutoff;
		}
		return getGrad(lfMin);
	}
	
	public double maxDerivRange(double lfMin, double lfMax)
	{
		if(lfMin < m_lfCutoff) {
			return 0.0;
		}
		return getGrad(lfMax);
	}
	
	public ICommStrengthFunc makeCopy() {
		return new ExpCommStrength(this);
	}
	

}