When the property ShadowPrice of a contraint is set or when the option Always_store_marginals is set to on, the .ShadowPrice suffix contains the shadow price of the constraint as computed by the solver. The shadow price of a constraint is the marginal change in the objective value with respect to a change in the right-hand side of the constraint.


The value of the .ShadowPrice suffix is numeric.


The .ShadowPrice suffix has the same dimension and domain as that of the constraint at hand.


  • When a variable X has a definition the suffix can also be applied to X but this is not encouraged by the syntax highlighting. The preferred notation is X_definition.ShadowPrice.

  • The GAMS equivalent suffix name is .m.

  • The default of the option Always_store_basics is off.

  • See also Constraint Declaration and Attributes of the Language Reference.