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)
```

*bayesSurv*version 3.7 Index]