Revision 12acd76ec1d613505e4bb20b3012e8d8507a310a authored by Lars Kotthoff on 16 May 2018, 20:38:09 UTC, committed by cran-robot on 16 May 2018, 20:38:09 UTC
1 parent 970c4e6
search.greedy.R
forward.search <- function(attributes, eval.fun) {
return(greedy.search(attributes, eval.fun, TRUE))
}
backward.search <- function(attributes, eval.fun) {
return(greedy.search(attributes, eval.fun, FALSE))
}
greedy.search <- function(attributes, eval.fun, forward = TRUE) {
if(length(attributes) == 0)
stop("Attributes not specified")
eval.fun = match.fun(eval.fun)
best = list(
result = -Inf,
attrs = rep(as.numeric(!forward), length(attributes))
)
# initial evaluation for full set when backward
if(!forward) {
best$result = eval.fun(attributes[as.logical(best$attrs)])
}
forward_text = ifelse(forward, "forward", "backward")
# main loop
repeat {
# create new matrix of children to evaluate
children = create.children(best$attrs, forward_text)
if(is.null(children))
break()
# evaluate and find the best of them
children_results = apply(children, 1, function(vec) {
eval.fun(attributes[as.logical(vec)])
})
local_best = find.best(children_results)
# compare to the best so far
if(local_best$result > best$result) {
best$result = local_best$result
best$attrs = children[local_best$idx,]
} else {
break()
}
}
return(attributes[as.logical(best$attrs)])
}
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