vecr2matr: Transform single component indeces to double component...

In bayesSurv: Bayesian Survival Regression with Flexible Error and Random Effects Distributions

Transform single component indeces to double component indeces

Description

Components of a bivariate G-spline can be indexed in several ways. Suppose that the knots in the first dimension are mu[1,-K1],...,mu[1,K1] and the knots in the second dimension mu[2,-K2],...,mu[2,K2]. I.e. we have 2*K[1]+1 knots in the first dimension and 2*K[2]+1 knots in the second dimension. Each G-spline component can have a double index (k[1],k[2]) assigned which means that it corresponds to the knot (mu[1,k1], mu[2,k2]) or alternatively the same G-spline component can have a~single index

r=(k[2]+K[2])*(2*K[1]+1) + k[1] + K[1] + 1

assigned where r takes values from 1,...,K[1]*K[2]. Single indexing is used for example by files r.sim and r_2.sim generated by functions bayesHistogram, bayesBisurvreg, bayessurvreg2 to save some space.

This function serves to translate single indeces to double indeces using the relationship

k[1] = (r-1) %% (2*K[1]+1) - K[1]

k[2] = (r-1) %\ % (2*K[1]+1) - K[2]

The function can be used also in one dimensional case when a~simple relationship holds

r = k + K + 1

k = r - 1 - K

Usage

vecr2matr(vec.r, KK)

Arguments

vec.r	a~vector of single indeces
KK	a~vector with numbers of knots on each side of the central knot for each dimension of the G-spline. The length of KK determines dimension of the G-spline

Value

In bivariate case: a~matrix with two columns and as many rows as the length of vec.r.

In univariate case: a~vector with as ,amy components as the length of vec.r.

Author(s)

Arnošt Komárek [e-mail]

Examples

### Bivariate G-spline
### with 31 knots in each dimension
KK <- c(15, 15)

### First observation in component (-15, -15),
### second observation in component (15, 15),
### third observation in component (0, 0)
vec.r <- c(1, 961, 481)
vecr2matr(vec.r, KK)

bayesSurv documentation built on Dec. 5, 2022, 5:22 p.m.