Logistic function helpers

Compute a logistic function or its derivative

logistic(xi, u_log, s_log)

logistic_deriv(xi, u_log, s_log)

Arguments

xi	X vector
u_log	Inflexion point (x-value of the sigmoid's midpoint)
s_log	Steepness of the curve

Value

logistic

Logistic function

logistic_deriv

Derivative of the Logistic function

See also

More informations can be found in the wikipedia page

Examples

logistic(1:10,5,0.1)
#>  [1] 4.248354e-18 9.357623e-14 2.061154e-09 4.539787e-05 5.000000e-01
#>  [6] 9.999546e-01 1.000000e+00 1.000000e+00 1.000000e+00 1.000000e+00
logistic_deriv(1:10,5,0.1)
#>  [1] 0.000000e+00 9.357623e-13 2.061154e-08 4.539581e-04 2.500000e+00
#>  [6] 4.539581e-04 2.061154e-08 9.357623e-13 4.248354e-17 1.928750e-21