Defines IVarianceFunction classes.
 
Returns 1.0 as variance value.
 
double variance(double, double) const override
 
VarianceConstantFunction * clone() const override
 
Returns max(sim, epsilon)
 
double variance(double exp, double sim) const override
 
VarianceSimFunction * clone() const override
 
VarianceSimFunction(double epsilon=1.0)