A.50.2 Delayed column generation

Delayed column generation means that more constraint columns are added to an existing LP. The following predicates are frequently used when this method is applied:

constraint(+Name, +Constraint, +S0, -S)

Like constraint/3, and attaches the name Name (an atom or compound term) to the new constraint.

shadow_price(+State, +Name, -Value)

Unifies Value with the shadow price corresponding to the linear constraint whose name is Name. State must correspond to a solved instance.

constraint_add(+Name, +Left, +S0, -S)

Left is a list of Coefficient*Variable terms. The terms are added to the left-hand side of the constraint named Name. S is unified with the resulting state.

An example application of delayed column generation to solve a bin packing task is available from: metalevel.at/various/colgen/