smoothSurv (version 2.6)

c2a: Work Function for 'smoothSurvReg'

Description

Compute the 'a' G-spline coefficients from 'c' G-spline coefficients.

Usage

c2a(ccoef, which.zero = which.max(ccoef), toler = 1e-6)

Value

A vector of same length as ccoef with 'a' G-spline coefficients.

Arguments

ccoef

A vector of 'c' G-spline coefficients.

which.zero

An index of the 'a' G-spline coefficient which will be zero (the reference one).

toler

All 'c' coefficients smaller in absolute value than toler are changed into toler (to avoid log(0)).

Author

Arnošt Komárek

Details

'c' and 'a' G-spline coefficients are related by the expression $$c_j = \frac{\exp(a_j)}{\sum_{l=1}^{g}\exp(a_l)}, j = 1,\dots, g,$$ where \(a_k = 0,\) k = which.zero. This function transforms the 'c' coefficients into their 'a' counterparts.

See Also

a2c

Examples

ccoef <- c(0.1, 0.2, 0.15, 0.3, 0.25)

### Compute 'a' counterparts
acoef <- c2a(ccoef, 1)
print(acoef)

### And back 'c', ccoef2 should be same as ccoef
ccoef2 <- a2c(acoef)
print(ccoef2)