decay {dyntaper}

Decay function delta

Description

Calculates (1 - p*x)_+^{1/p}, or its limit exp(-x) when p tends to 0.

Usage

decay(x, p)

Arguments

x

Input value(s), possibly a vector.

p

Parameter.

Details

Perhaps overkill, but uses log1p() function for better accuracy than the more obvious formula.

Value

Decay function value(s).

Examples

   decay(2, 0) == exp(-2)
   decay(1.5, 0.5)
   decay(2.5, 0.5)
   decay(2.5, -0.5)
   for(p in seq(1, -1, -0.5)) curve(decay(x, p), 0, 3, add=(p != 1))