gurobipy.TempConstr#

classTempConstr#

Gurobi temporary constraint object. Objects of this class are created asintermediate results when building constraints using overloadedoperators. There are no member functions on this class. Instead,TempConstr objects are created by a set of functions onVar,MVar,LinExpr,QuadExpr,MLinExpr,MQuadExpr, andGenExpr objects (e.g.,==,<=, and>=). Youwill generally never store objects of this class in your own variables.

TheTempConstr object allows you to create several different typesof constraints:

• Linear Constraint: an expression of the formExpr1senseExpr2, whereExpr1 andExpr2 areLinExpr objects,Var objects, or constants,andsense is one of==,<= or>=. For example,x+y<=1+z is a linear constraint, as isx+y==5. NotethatExpr1 andExpr2 can’t both be constants.

• Ranged Linear Constraint: an expression of the formLinExpr==[Const1,Const2], whereConst1 andConst2 areconstants andLinExpr is aLinExpr object. Forexample,x+y==[1,2] is a ranged linear constraint.

• Quadratic Constraint: an expression of the formExpr1senseExpr2, whereExpr1 andExpr2 areQuadExpr objects,LinExpr objects,Var objects, or constants, andsense is one of==,<= or>=. For example,x*x+y*y<=3 is aquadratic constraint, as isx*x+y*y<=z*z. Note that one ofExpr1 orExpr2 must be aQuadExpr (otherwise, theconstraint would be linear).

• Linear Matrix Constraint: an expression of the formExpr1senseExpr2, where one or both ofExpr1 andExpr2areMLinExpr objects andsense is one of==,<= or>=. For example,A@x<=1 is a linear matrixconstraint, as isA@x==B@y.

• Quadratic Matrix Constraint: an expression of the formExpr1senseExpr2, where one or both ofExpr1 andExpr2areMQuadExpr objects andsense is one of==,<= or>=. For example,x@Q@y<=3 is a quadraticconstraint, as isx@Q@x<=y@A@y.

• Absolute Value Constraint: an expression of the formx==abs_(y), wherex andy must beVarobjects.

• Logical Constraint: an expression of the formx==op_(y),wherex is a binaryVar object, andy is a binaryVar, a list of binaryVar, or atupledict of binaryVar, andop_ iseitherand_ oror_.

• Min or Max Constraint: an expression of the formx==op_(y),wherex is aVar object, andy is aVar, a list ofVar and constants, or atupledict ofVar, andop_ is one ofmin_ ormax_.

• Indicator Constraint: an expression of the form(x==b)>>(Expr1senseExpr2), wherex is a binaryVar object,b is either0 or1;Expr1 andExpr2 areLinExpr objects,Var objects,or constants, andsense is one of==,<= or>=.Parenthesizing both expressions is required. For example,(x==1)>>(y+w<=5) is an indicator constraint, indicatingthat whenever the binary variablex takes the value1 thenthe linear constrainty+w<=5 must hold.

Consider the following examples:

model.addConstr(x+y==1);model.addConstr(x+y==[1,2]);model.addConstr(x*x+y*y<=1);model.addConstr(A@x<=1);model.addConstr(x@A@x<=1);model.addConstr(x==abs_(y));model.addConstr(x==or_(y,z));model.addConstr(x==max_(y,z));model.addConstr((x==1)>>(y+z<=5));

In each case, the overloaded comparison operator creates an object oftypeTempConstr, which is then immediately passed to methodModel.addConstr.