As logisticdupbyx, but faster when distance is a covariate
(but no interactions with distance occur.
logisticdupbyx_fast(distance, x1, x2, models, beta, point, beta_distance)vector of distance values
linear predictor for 1, without distance
linear predictor for 2, without distance
model list
logistic parameters
TRUE for point transect data
parameter for distance
David L Miller