#' @rdname model_generic
#' @export
model_dk_nhl <- function(data, ...) {
# params
total_salary <- 50E3
roster_size <- 9
max_from_team <- 5
# build model
model <- model_generic(data, total_salary, roster_size, max_from_team, ...) %>%
add_dk_nhl_roster_positions_constraint(data)
model
}
#' @importFrom ompr add_constraint sum_expr colwise
#' @keywords internal
add_dk_nhl_roster_positions_constraint <- function(model, nhl) {
# check position names
assert_has_positions(nhl, c("C", "LW", "RW", "D", "G"))
# position constraint helpers
n <- nrow(nhl)
is_position <- function(pos) {
function(i) {
as.integer(pos == nhl$position[i])
}
}
Ctr <- is_position("C")
LW <- is_position("LW")
RW <- is_position("RW")
D <- is_position("D")
G <- is_position("G")
model %>%
# Center
add_constraint(sum_expr(colwise(Ctr(i)) * x[i], i = 1:n) >= 2) %>%
add_constraint(sum_expr(colwise(Ctr(i)) * x[i], i = 1:n) <= 3) %>%
# Wings
add_constraint(sum_expr(colwise(LW(i) + RW(i)) * x[i], i = 1:n) >= 3) %>%
add_constraint(sum_expr(colwise(LW(i) + RW(i)) * x[i], i = 1:n) <= 4) %>%
# Defender
add_constraint(sum_expr(colwise(D(i)) * x[i], i = 1:n) >= 2) %>%
add_constraint(sum_expr(colwise(D(i)) * x[i], i = 1:n) <= 3) %>%
# Goalie
add_constraint(sum_expr(colwise(G(i)) * x[i], i = 1:n) == 1)
}
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