Gurobi——GRBModel

GRBModel

  Gurobi Model object . Common methods include addVar（ Add a new decision variable to the model ）、addConstr（ Add a new constraint to the model ）、optimize（ Optimize the current model ）、get（ Retrieve the value of a property ）.

GRBModel GRBModel(const GRBEnv& env)

Model constructor .

Parameters	Detailed explanation
env	The environment of the new model .
Return value	New model object . The model does not initially contain variables or constraints .

GRBModel GRBModel(const GRBEnv& env,
 	  			  const string& filename)

   Read the model from the file . Please note that , The type code of the file is in the suffix of the file name . Valid suffixes are .mps、.rew、.lp、.rlp、.dua、.dlp、.ilp or .opb. These files can be compressed , Therefore, additional .zip、.gz、.bz2 or .7z suffix .

Parameters	Detailed explanation
env	The environment of the new model .
modelname	The name of the file containing the model .
Return value	New model object .

GRBModel GRBModel(const GRBModel& model)

Create a copy of an existing model . Please note that , because Gurobi Lazy update method in , You must call before copying. update .

Parameters	Detailed explanation
model: Models that need to be copied .
Return value	New model object . A model is a clone of an input model .

---

GRBModel::addConstr()

Add a single linear constraint to the model . Multiple signatures （signatures） You can use .

•   GRBConstr 	addConstr(const GRBLinExpr& lhsExpr,
    			  	  	  char sense,
    			  	  	  const GRBLinExpr& rhsExpr,
    			  	  	  string name="" )
  

  Add a single linear constraint to the model .

  Parameters	Detailed explanation
  lhsExpr	Left expression of the new linear constraint .
  sense	New linear perceptual constraints （GRB_LESS_EQUAL、GRB_EQUAL or GRB_GREATER_EQUAL）.
  rhsExpr	Right expression of the new linear constraint .
  names（ Optional ）	The name of the new constraint .
  Return value	New constraint object .

•   GRBConstr addConstr(const GRBLinExpr&	lhsExpr,
    			  	  	char 	sense,
    			  	  	GRBVar 	rhsVar,
    			  	  	string 	name="" )
  

  Add a single linear constraint to the model .

  Parameters	Detailed explanation
  lhsExpr	Left expression of the new linear constraint .
  sense	New linear perceptual constraints （GRB_LESS_EQUAL、GRB_EQUAL or GRB_GREATER_EQUAL）.
  rhsVar	Right variable of the new linear constraint .
  name（ Optional ）	The name of the new constraint .
  Return value	New constraint object .

•   GRBConstr addConstr (const GRBLinExpr& 	lhsExpr,
    				  	   char 	sense,
    				  	   double 	rhsVal,
    				  	   string 	name="")
  

  Add a single linear constraint to the model .

  Parameters	Detailed explanation
  lhsExpr	Left expression of the new linear constraint .
  sense	New linear perceptual constraints （GRB_LESS_EQUAL、GRB_EQUAL or GRB_GREATER_EQUAL）.
  rhsVal	The right value of the new linear constraint .
  name（ Optional ）	The name of the new constraint .
  Return value	New constraint object .

•   GRBConstr addConstr(GRBVar 	lhsVar,
    			  	  	  char 	sense,
    			  	  	  GRBVar 	rhsVar,
    			  	  	  string 	name="" )
  

  Add a single linear constraint to the model .

  Parameters	Detailed explanation
  lhsVar	Left variable of the new linear constraint .
  sense	New linear perceptual constraints （GRB_LESS_EQUAL、GRB_EQUAL or GRB_GREATER_EQUAL）.
  rhsVar	Right variable of the new linear constraint .
  name（ Optional ）	The name of the new constraint .
  Return value	New constraint object .

•   GRBConstr addConstr(GRBVar 	lhsVar,
    			  	  	  char 	sense,
    			  	  	  double 	rhsVal,
    			  	  	  string 	name="")
  

  Add a single linear constraint to the model .

  Parameters	Detailed explanation
  lhsVar	Left variable of the new linear constraint .
  sense	New linear perceptual constraints （GRB_LESS_EQUAL、GRB_EQUAL or GRB_GREATER_EQUAL）.
  rhsVal	The right value of the new linear constraint .
  name（ Optional ）	The name of the new constraint .
  Return value	New constraint object .

•   GRBConstr addConstr(GRBTempConstr& 	tc,
      	  			  string 	name="")
  

  Add a single linear constraint to the model .

  Parameters	Detailed explanation
  tc	Temporary constraint object , Create using overloaded comparison operators . For more information , see also GRBTempConstr.
  name（ Optional ）	The name of the new constraint .
  Return value	New constraint object .

---

GRBModel::addVar()

Add a single decision variable to the model .
Templates 1

GRBVar 	addVar (double 	lb,
		  	  	double 	ub,
		  	  	double 	obj,
		  	  	char 	type,
		  	  	string 	name="" )

Add a variable ; Non zero entries will be added later .

Parameters	Detailed explanation
lb	The lower bound of the new variable .
ub	The upper limit of the new variable .
obj	The objective coefficient of the new variable .
type	The variable type of the new variable （GRB_CONTINUOUS、GRB_BINARY、GRB_INTEGER、GRB_SEMICONT or GRB_SEMIINT）.
names（ Optional ）	The name of the new variable .
Return value	New variable object .

Templates 2

GRBVar 	addVar (double 	lb,
		  	  	double 	ub,
		  	  	double 	obj,
		  	  	char 	type,
		  	  	int 	numnz,
		  	  	const GRBConstr* constrs,
		  	  	const double* 	 coeffs,
		  	  	string 	name="" )

Add a variable , And the associated non-zero coefficient .

Parameters	Detailed explanation
lb	The lower bound of the new variable .
ub	The upper limit of the new variable .
obj	The objective coefficient of the new variable .
type	The variable type of the new variable （GRB_CONTINUOUS、GRB_BINARY、GRB_INTEGER、GRB_SEMICONT or GRB_SEMIINT）.
numnz	The number of constraints this new variable participates in .
constrs	Constraint array with variable participation .
coeffs	An array of coefficients for each constraint in which the variable participates .
names（ Optional ）	The name of the new variable .
Return value	New variable object .

Templates 3

GRBVar 	addVar (double 	lb,
		  	  	double 	ub,
		  	  	double 	obj,
		  	  	char 	type,
		  	  	const GRBColumn& 	col,
		  	  	string 	name="" )

Add a variable , And the associated non-zero coefficient .

Parameters	Detailed explanation
lb	The lower bound of the new variable .
ub	The upper limit of the new variable .
obj	The objective coefficient of the new variable .
type	The variable type of the new variable （GRB_CONTINUOUS、GRB_BINARY、GRB_INTEGER、GRB_SEMICONT or GRB_SEMIINT）.
col	GRBColumn object , Specifies the set of constraints to which the new variable belongs .
names（ Optional ）	The name of the new variable .
Return value	New variable object .

---

GRBModel::addVars()

Add new decision variables to the model .

Templates 1

GRBVar*	addVars(int count,	
				char type=GRB_CONTINUOUS)

   Add to model count A new decision variable . All associated properties adopt their default values , Except for variable types , It is specified as a parameter .

Parameters	Detailed explanation
count	Number of variables to add
type ( Optional )	Type of newly added variable , optional type : GRB_CONTINUOUS, GRB_BINARY, GRB_INTEGER, GRB_SEMICONT, or GRB_SEMIINT
Return value	Array of new variable objects . Please note that , The result is heap allocated , And must be returned to the heap by the user .

Templates 2

GRBVar* addVars(const double*  lb,
				const double*  ub,
				const double*  obj,
			    const char*  type,
				const string* names,
				int count )

   Add a new decision variable to the model . This function name allows the use of arrays to hold various variable properties （ For example, lower limit 、 Upper limit, etc ）.

Parameters	Detailed explanation
lb	The lower bound of the new variable . It can be for NULL, under these circumstances , The lower bound of the variable is 0.0.
ub	The upper limit of the new variable . It can be for NULL, under these circumstances , Variable gets an infinite upper bound .
obj	The objective coefficient of the new variable （Objective coefficients）. It can be for NULL, under these circumstances , The objective coefficient of the variable is 0.0.
type	The variable type of the new variable （GRB_CONTINUOUS、GRB_BINARY、GRB_INTEGER、GRB_SEMICONT or GRB_SEMIINT）. It can be for NULL, In this case, the variables are assumed to be continuous .
names	The name of the new variable . It can be for NULL, under these circumstances , All variables are given default names .
count	Number of variables to add .
Return value	Array of new variable objects . Please note that , The result is heap allocated , And must be returned to the heap by the user .

Templates 3

GRBVar* addVars(const double*  lb,
  	  			const double*  ub,
  	  			const double*  obj,
  	  			const char*    type,
  	  			const string*  names,
  	  			const GRBColumn* cols,
  	  			int   count )

   Add new decision variables to the model . This function allows the use of GRBColumn Object array specifies the set of constraints to which each new variable belongs .

Parameters	Detailed explanation
lb	The lower bound of the new variable . It can be for NULL, under these circumstances , The lower bound of the variable is 0.0.
ub	The upper limit of the new variable . It can be for NULL, under these circumstances , Variable gets an infinite upper bound .
obj	The objective coefficient of the new variable . It can be for NULL, under these circumstances , The objective coefficient of the variable is 0.0.
type	The variable type of the new variable （GRB_CONTINUOUS、GRB_BINARY、GRB_INTEGER、GRB_SEMICONT or GRB_SEMIINT）. It can be for NULL, In this case, the variables are assumed to be continuous .
names	The name of the new variable . It can be for NULL, under these circumstances , All variables are given default names .
cols	GRBColumn object , Specifies the set of constraints to which each new column belongs .
count	Number of variables to add .
Return value	Array of new variable objects . Please note that , The result is heap allocated , And must be returned to the heap by the user .

Reference resources

1. C++ API Details
2. GRBModel::addVar()
3. GRBModel::addVars()