tree_update: tree_update
In pierrejacob/PET:

Description Usage Arguments Details Value Examples

View source: R/trees.R

This function updates a tree given new particles and ancestors. This is achieved by pruning the tree first, then inserting the new particles according to their respective ancestors.

1	tree_update(tree, X_t, a_t)

`tree`	is a `list` encoding a tree genereated via the function `tree_init` or previously updated via the function `tree_update`
`X_t`	is a `dimX` by `N` matrix representing a set of `N` new `dimX`-dimensional particles.
`a_t`	is a vector of length `N` containing the indices of the new particles' ancestors.

See documentation of tree_init for a description of the tree's fields. See also Path storage in the particle filter, by Jacob, Murray, Rubenthaler (2015) [https://link.springer.com/article/10.1007/s11222-013-9445-x]

This function outputs the tree with updated fields (see details).

N = 5
dimX = 2
X_0 = matrix(rnorm(N*dimX), nrow = dimX, ncol = N)
X_1 = matrix(rnorm(N*dimX), nrow = dimX, ncol = N)
a_1 = sample(1:N, size = N, replace = TRUE)
tree = tree_init(X_0)
tree = tree_update(tree, X_1, a_1)