| vecr2matr {bayesSurv} | R Documentation |
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,-K_1},\dots,\mu_{1,K_1}
and the knots in the second dimension
\mu_{2,-K_2},\dots,\mu_{2,K_2}.
I.e. we have 2K_1+1 knots in the first dimension and
2K_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,k_1},\mu_{2,k_2})
or alternatively the same G-spline component can have a~single index
r=(k_2 + K_2)\times(2K_1+1) + k_1 + K_1 + 1
assigned where r takes values from
1,\dots,K_1\times 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) \mbox{ mod } (2K_1+1) - K_1
k_2 = (r - 1) \mbox{ div } (2K_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 |
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 arnost.komarek@mff.cuni.cz
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)