Changes the behavior of lazy updates. By default, whenever you add a
new variable or constraint to the model, you must call
update before you can access that new item. For example,
you must call
update before you can build a new constraint that
involves a newly added variable. Setting the new
parameter to 1 allows you to use new variables and constraints
immediately for building or modifying the model. Note that the current model
is still not changed and so the attributes about the new variables and
constraints cannot be queried, until
update is called.
Note that it is generally a good idea to add items to your Gurobi
model in phases, calling
update at the end of each phase. This
practice allows Gurobi to build the internal representation of your
model more efficiently. This new parameter is meant for cases where
adding items in phases is inconvenient. It introduces a small amount
of additional internal storage, and can introduce a small performance
overhead. It may also cause Gurobi to make less aggressive use of
warm-start information when modifying models and resolving using simplex.
You should set this parameter as soon as you create your Gurobi environment.
Note that you still need to call
update to modify an attribute
on an SOS constraint or a quadratic constraint.
For examples of how to query or modify parameter values from our different APIs, refer to our Parameter Examples.