#' @rdname model_generic
#' @export
model_dk_nfl <- function(data, existing_rosters = list()) {
# params
total_salary <- 50E3
roster_size <- 9L
max_from_team <- 4L
# build model
model_generic(data, total_salary, roster_size, max_from_team, existing_rosters) %>%
add_dk_nfl_roster_positions_constraint(data)
}
#' @importFrom ompr add_constraint sum_expr
#' @keywords internal
add_dk_nfl_roster_positions_constraint <- function(model, nfl) {
# position constraint helpers
n <- nrow(nfl)
is_position <- function(pos) {
function(i) {
as.integer(pos == nfl$position[i])
}
}
QB <- is_position("QB")
RB <- is_position("RB")
WR <- is_position("WR")
TE <- is_position("TE")
DST <- is_position("DST")
model %>%
# quater back
add_constraint(sum_expr(colwise(QB(i)) * x[i], i = 1:n) == 1) %>%
# running back
add_constraint(sum_expr(colwise(RB(i)) * x[i], i = 1:n) >= 2) %>%
add_constraint(sum_expr(colwise(RB(i)) * x[i], i = 1:n) <= 3) %>%
# wide receiver
add_constraint(sum_expr(colwise(WR(i)) * x[i], i = 1:n) >= 3) %>%
add_constraint(sum_expr(colwise(WR(i)) * x[i], i = 1:n) <= 4) %>%
# tight end
add_constraint(sum_expr(colwise(TE(i)) * x[i], i = 1:n) >= 1) %>%
add_constraint(sum_expr(colwise(TE(i)) * x[i], i = 1:n) <= 2) %>%
# defense
add_constraint(sum_expr(colwise(DST(i)) * x[i], i = 1:n) == 1)
}
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