Replace the tail of a distribution.
graft_right() keeps the left cdf unchanged to the left of
sep_y, and makes a continuous connection with the right cdf
(rescaled as appropriate).
graft_left() keeps the right cdf unchanged to the right of
sep_y, and makes a continuous connection with the left cdf
(rescaled as appropriate),
graft_right(dst_left, dst_right, sep_y) is_graft(object) is.graft(object)
Distributions to connect
Value on the domain of the cdf to connect at.
Object to be tested
A grafted distribution object.