Logdecay

Purpose

Scales a matrix using the inverse log decay of the variable axis.

Synopsis

[sx,logscl] = logdecay(x,tau)

Description

Inputs are data to be scaled (x), and the decay rate (tau). Outputs are the variance scaled matrix (sx) and the log decay based variance scaling parameters (logscl).

For an m x n matrix 'x' the variance scaling used for variable 'i' is exp(-(i-1)/((n-1)\*tau)). This gives a scaling of 1 on the first variable (i.e. no scaling), and a scaling of 1/exp(-1/tau) on the last variable. The following table gives example values of tau and the scaling which is applied to the last column of x (the last variable):

tau	scaling
1	2.7183
1/2	7.3891
1/3	20.0855
1/4	54.5982
1/5	148.4132

See Also

auto, scale