smoothSurv (version 2.6)

give.c: Work Function for 'smoothSurvReg'

Description

Give a vector of all 'c' G-spline coefficients satisfying the three constrains (see below) if only (g-3) c's are given.

Usage

give.c(knots, sdspline, last.three, c.rest)

Value

A vector of all length(knots) 'c' G-spline coefficients.

Arguments

knots

A vector of G-spline knots \(\mu\).

sdspline

Standard deviation \(\sigma_0\) of the basis G-spline.

last.three

Indeces of the three 'c' G-spline coefficients which are not included in c.rest. This must be a vector of length 3 with three different numbers from 1:length(knots).

c.rest

A vector of length(knots) - 3 'c' spline coefficients corresponding to knots knots[-last.three]. They must all lie between zero and one and their sum must be lower or equal to one.

Author

Arnošt Komárek

Details

The functions computes remaining three 'c' G-spline coefficients (if it is possible) such that the resulting G-spline satisfies the following: $$\sum_{j=1}^g c_j = 1,$$ $$\sum_{j=1}^g c_j \mu_j = 0,$$ $$\sum_{j=1}^g c_j \mu_j^2 = 1 - \sigma_0^2.$$

Examples

knots <- seq(-4, 4, 0.5)
sd0 <- 0.3
ccoef <- find.c(knots, sd0, dist = "dstlogis")

last.three <- c(3, 7, 10)
c.rest <- ccoef[-last.three]
ccoef2 <- give.c(knots, sd0, last.three, c.rest)

print(ccoef)
print(ccoef2)    ## Almost no change