: contains the dual solution vector. The magnitude of
gives a measure of the improvement in the objective value if the corresponding bound were to be relaxed so that
could take different values.
A value of
equal to the special value
is indicative of the matrix
not having full rank. It is only likely to occur when
. However a matrix may have less than full rank without
being set to
. If
, then the values contained in
w (other than those set to
) may be unreliable; the corresponding values in
indx may likewise be unreliable. If you have any doubts set
. Otherwise, the values of
have the following meaning:
- if is unconstrained.
- if is constrained by its lower bound.
- if is constrained by its upper bound.
- may be any value if .