Java Reference
Java Reference
Detailed Description
This mathematical programming (MP) solver class is the main class
though which users build and solve problems.
Definition at line 17 of file MPSolver.java.
Classes | |
| enum | BasisStatus |
| Advanced usage: possible basis status values for a variable and the slack variable of a linear constraint. More... | |
| enum | OptimizationProblemType |
| The type of problems (LP or MIP) that will be solved and the underlying solver (GLOP, GLPK, CLP, CBC or SCIP) that will solve them. More... | |
| enum | ResultStatus |
| The status of solving the problem. More... | |
Public Member Functions | |
| synchronized void | delete () |
| MPVariable[] | makeVarArray (int count, double lb, double ub, boolean integer) |
| Creates and returns an array of variables. More... | |
| MPVariable[] | makeVarArray (int count, double lb, double ub, boolean integer, String var_name) |
| Creates and returns an array of named variables. More... | |
| MPVariable[] | makeNumVarArray (int count, double lb, double ub) |
| MPVariable[] | makeNumVarArray (int count, double lb, double ub, String var_name) |
| MPVariable[] | makeIntVarArray (int count, double lb, double ub) |
| MPVariable[] | makeIntVarArray (int count, double lb, double ub, String var_name) |
| MPVariable[] | makeBoolVarArray (int count) |
| MPVariable[] | makeBoolVarArray (int count, String var_name) |
| MPSolver (String name, MPSolver.OptimizationProblemType problem_type) | |
| Create a solver with the given name and underlying solver backend. More... | |
| void | clear () |
| Clears the objective (including the optimization direction), all variables and constraints. More... | |
| int | numVariables () |
| Returns the number of variables. More... | |
| MPVariable[] | variables () |
| Returns the array of variables handled by the MPSolver. More... | |
| MPVariable | lookupVariableOrNull (String var_name) |
| Looks up a variable by name, and returns nullptr if it does not exist. More... | |
| MPVariable | makeVar (double lb, double ub, boolean integer, String name) |
| Creates a variable with the given bounds, integrality requirement and name. More... | |
| MPVariable | makeNumVar (double lb, double ub, String name) |
| Creates a continuous variable. More... | |
| MPVariable | makeIntVar (double lb, double ub, String name) |
| Creates an integer variable. More... | |
| MPVariable | makeBoolVar (String name) |
| Creates a boolean variable. More... | |
| int | numConstraints () |
| Returns the number of constraints. More... | |
| MPConstraint[] | constraints () |
| Returns the array of constraints handled by the MPSolver. More... | |
| MPConstraint | lookupConstraintOrNull (String constraint_name) |
| Looks up a constraint by name, and returns nullptr if it does not exist. More... | |
| MPConstraint | makeConstraint (double lb, double ub) |
| Creates a linear constraint with given bounds. More... | |
| MPConstraint | makeConstraint () |
| Creates a constraint with -infinity and +infinity bounds. More... | |
| MPConstraint | makeConstraint (double lb, double ub, String name) |
| Creates a named constraint with given bounds. More... | |
| MPConstraint | makeConstraint (String name) |
| Creates a named constraint with -infinity and +infinity bounds. More... | |
| MPObjective | objective () |
| Returns the mutable objective object. More... | |
| MPSolver.ResultStatus | solve () |
| Solves the problem using the default parameter values. More... | |
| MPSolver.ResultStatus | solve (MPSolverParameters param) |
| Solves the problem using the specified parameter values. More... | |
| double[] | computeConstraintActivities () |
| Advanced usage: compute the "activities" of all constraints, which are the sums of their linear terms. More... | |
| boolean | verifySolution (double tolerance, boolean log_errors) |
| Advanced usage: Verifies the correctness of the solution. More... | |
| void | reset () |
| Advanced usage: resets extracted model to solve from scratch. More... | |
| boolean | interruptSolve () |
| Interrupts the Solve() execution to terminate processing if possible. More... | |
| boolean | setSolverSpecificParametersAsString (String parameters) |
| Advanced usage: pass solver specific parameters in text format. More... | |
| void | enableOutput () |
| Enables solver logging. More... | |
| void | suppressOutput () |
| Suppresses solver logging. More... | |
| long | iterations () |
| Returns the number of simplex iterations. More... | |
| long | nodes () |
| Returns the number of branch-and-bound nodes evaluated during the solve. More... | |
| double | computeExactConditionNumber () |
| Advanced usage: computes the exact condition number of the current scaled basis: L1norm(B) * L1norm(inverse(B)), where B is the scaled basis. More... | |
| void | setTimeLimit (long time_limit_milliseconds) |
| long | wallTime () |
| String | loadModelFromProto (com.google.ortools.linearsolver.MPModelProto input_model) |
| Loads a model and returns the error message, which will be empty iff the model is valid. More... | |
| String | loadModelFromProtoWithUniqueNamesOrDie (com.google.ortools.linearsolver.MPModelProto input_model) |
| com.google.ortools.linearsolver.MPModelProto | exportModelToProto () |
| Export the loaded model to proto and returns it. More... | |
| com.google.ortools.linearsolver.MPSolutionResponse | createSolutionResponseProto () |
| Fills the solution found to a response proto and returns it. More... | |
| boolean | loadSolutionFromProto (com.google.ortools.linearsolver.MPSolutionResponse response) |
| Load a solution encoded in a protocol buffer onto this solver for easy access via the MPSolver interface. More... | |
| String | exportModelAsLpFormat (MPModelExportOptions options) |
| Export the loaded model in LP format. More... | |
| String | exportModelAsLpFormat () |
| Export the loaded model in LP format. More... | |
| String | exportModelAsMpsFormat (MPModelExportOptions options) |
| Export the loaded model in MPS format. More... | |
| String | exportModelAsMpsFormat () |
| Export the loaded model in MPS format. More... | |
| void | setHint (MPVariable[] variables, double[] values) |
| Sets a hint for solution. More... | |
| boolean | setNumThreads (int num_theads) |
| Sets the number of threads to be used by the solver. More... | |
Static Public Member Functions | |
| static boolean | supportsProblemType (MPSolver.OptimizationProblemType problem_type) |
| Whether the given problem type is supported (this will depend on the targets that you linked). More... | |
| static double | infinity () |
| Infinity. More... | |
| static com.google.ortools.linearsolver.MPSolutionResponse | solveWithProto (com.google.ortools.linearsolver.MPModelRequest model_request) |
| Solves the given model proto and returns a response proto. More... | |
Protected Member Functions | |
| MPSolver (long cPtr, boolean cMemoryOwn) | |
Constructor & Destructor Documentation
◆ MPSolver() [1/2]
|
inlineprotected |
Definition at line 21 of file MPSolver.java.
◆ MPSolver() [2/2]
|
inline |
Create a solver with the given name and underlying solver backend.
Definition at line 95 of file MPSolver.java.
Member Function Documentation
◆ clear()
|
inline |
Clears the objective (including the optimization direction), all variables
and constraints.
All the other properties of the MPSolver (like the time
limit) are kept untouched.
Definition at line 112 of file MPSolver.java.
◆ computeConstraintActivities()
|
inline |
Advanced usage: compute the "activities" of all constraints, which are the
sums of their linear terms.
The activities are returned in the same order
as constraints(), which is the order in which constraints were added; but
you can also use MPConstraint::index() to get a constraint's index.
Definition at line 270 of file MPSolver.java.
◆ computeExactConditionNumber()
|
inline |
Advanced usage: computes the exact condition number of the current scaled
basis: L1norm(B) * L1norm(inverse(B)), where B is the scaled basis.
This method requires that a basis exists: it should be called after Solve.
It is only available for continuous problems. It is implemented for GLPK
but not CLP because CLP does not provide the API for doing it.
The condition number measures how well the constraint matrix is conditioned
and can be used to predict whether numerical issues will arise during the
solve: the model is declared infeasible whereas it is feasible (or
vice-versa), the solution obtained is not optimal or violates some
constraints, the resolution is slow because of repeated singularities.
The rule of thumb to interpret the condition number kappa is:
- o kappa <= 1e7: virtually no chance of numerical issues
- o 1e7 < kappa <= 1e10: small chance of numerical issues
- o 1e10 < kappa <= 1e13: medium chance of numerical issues
- o kappa > 1e13: high chance of numerical issues
The computation of the condition number depends on the quality of the LU
decomposition, so it is not very accurate when the matrix is ill
conditioned.
Definition at line 393 of file MPSolver.java.
◆ constraints()
|
inline |
Returns the array of constraints handled by the MPSolver.
They are listed in the order in which they were created.
Definition at line 189 of file MPSolver.java.
◆ createSolutionResponseProto()
|
inline |
Fills the solution found to a response proto and returns it.
Definition at line 436 of file MPSolver.java.
◆ delete()
|
inline |
Definition at line 35 of file MPSolver.java.
◆ enableOutput()
|
inline |
Enables solver logging.
Definition at line 342 of file MPSolver.java.
◆ exportModelAsLpFormat() [1/2]
|
inline |
Export the loaded model in LP format.
Definition at line 510 of file MPSolver.java.
◆ exportModelAsLpFormat() [2/2]
|
inline |
Export the loaded model in LP format.
Definition at line 503 of file MPSolver.java.
◆ exportModelAsMpsFormat() [1/2]
|
inline |
Export the loaded model in MPS format.
Definition at line 524 of file MPSolver.java.
◆ exportModelAsMpsFormat() [2/2]
|
inline |
Export the loaded model in MPS format.
Definition at line 517 of file MPSolver.java.
◆ exportModelToProto()
|
inline |
Export the loaded model to proto and returns it.
Definition at line 420 of file MPSolver.java.
◆ infinity()
|
inlinestatic |
Infinity.
You can use -MPSolver::infinity() for negative infinity.
Definition at line 335 of file MPSolver.java.
◆ interruptSolve()
|
inline |
Interrupts the Solve() execution to terminate processing if possible.
If the underlying interface supports interruption; it does that and returns
true regardless of whether there's an ongoing Solve() or not. The Solve()
call may still linger for a while depending on the conditions. If
interruption is not supported; returns false and does nothing.
Definition at line 316 of file MPSolver.java.
◆ iterations()
|
inline |
Returns the number of simplex iterations.
Definition at line 356 of file MPSolver.java.
◆ loadModelFromProto()
|
inline |
Loads a model and returns the error message, which will be empty iff the
model is valid.
Definition at line 409 of file MPSolver.java.
◆ loadModelFromProtoWithUniqueNamesOrDie()
|
inline |
Definition at line 413 of file MPSolver.java.
◆ loadSolutionFromProto()
|
inline |
Load a solution encoded in a protocol buffer onto this solver for easy
access via the MPSolver interface.
IMPORTANT: This may only be used in conjunction with ExportModel(),
following this example:
The response must be in OPTIMAL or FEASIBLE status.
Returns a false if a problem arised (typically, if it wasn't used
like it should be):
- loading a solution whose variables don't correspond to the solver's
current variables
- loading a solution with a status other than OPTIMAL / FEASIBLE.
Note: the objective value isn't checked. You can use VerifySolution() for
that.
Definition at line 480 of file MPSolver.java.
◆ lookupConstraintOrNull()
|
inline |
Looks up a constraint by name, and returns nullptr if it does not exist.
The first call has a O(n) complexity, as the constraint name index is
lazily created upon first use. Will crash if constraint names are not
unique.
Definition at line 200 of file MPSolver.java.
◆ lookupVariableOrNull()
|
inline |
Looks up a variable by name, and returns nullptr if it does not exist.
The
first call has a O(n) complexity, as the variable name index is lazily
created upon first use. Will crash if variable names are not unique.
Definition at line 136 of file MPSolver.java.
◆ makeBoolVar()
|
inline |
Creates a boolean variable.
Definition at line 172 of file MPSolver.java.
◆ makeBoolVarArray() [1/2]
|
inline |
Definition at line 84 of file MPSolver.java.
◆ makeBoolVarArray() [2/2]
|
inline |
Definition at line 88 of file MPSolver.java.
◆ makeConstraint() [1/4]
|
inline |
Creates a constraint with -infinity and +infinity bounds.
Definition at line 221 of file MPSolver.java.
◆ makeConstraint() [2/4]
|
inline |
Creates a linear constraint with given bounds.
Bounds can be finite or +/- MPSolver::infinity(). The MPSolver class
assumes ownership of the constraint.
- Returns
- a pointer to the newly created constraint.
Definition at line 213 of file MPSolver.java.
◆ makeConstraint() [3/4]
|
inline |
Creates a named constraint with given bounds.
Definition at line 229 of file MPSolver.java.
◆ makeConstraint() [4/4]
|
inline |
Creates a named constraint with -infinity and +infinity bounds.
Definition at line 237 of file MPSolver.java.
◆ makeIntVar()
|
inline |
Creates an integer variable.
Definition at line 164 of file MPSolver.java.
◆ makeIntVarArray() [1/2]
|
inline |
Definition at line 76 of file MPSolver.java.
◆ makeIntVarArray() [2/2]
|
inline |
Definition at line 80 of file MPSolver.java.
◆ makeNumVar()
|
inline |
Creates a continuous variable.
Definition at line 156 of file MPSolver.java.
◆ makeNumVarArray() [1/2]
|
inline |
Definition at line 68 of file MPSolver.java.
◆ makeNumVarArray() [2/2]
|
inline |
Definition at line 72 of file MPSolver.java.
◆ makeVar()
|
inline |
Creates a variable with the given bounds, integrality requirement and
name.
Bounds can be finite or +/- MPSolver::infinity(). The MPSolver owns
the variable (i.e. the returned pointer is borrowed). Variable names are
optional. If you give an empty name, name() will auto-generate one for you
upon request.
Definition at line 148 of file MPSolver.java.
◆ makeVarArray() [1/2]
|
inline |
Creates and returns an array of variables.
Definition at line 48 of file MPSolver.java.
◆ makeVarArray() [2/2]
|
inline |
Creates and returns an array of named variables.
Definition at line 59 of file MPSolver.java.
◆ nodes()
|
inline |
Returns the number of branch-and-bound nodes evaluated during the solve.
Only available for discrete problems.
Definition at line 365 of file MPSolver.java.
◆ numConstraints()
|
inline |
Returns the number of constraints.
Definition at line 180 of file MPSolver.java.
◆ numVariables()
|
inline |
Returns the number of variables.
Definition at line 119 of file MPSolver.java.
◆ objective()
|
inline |
Returns the mutable objective object.
Definition at line 245 of file MPSolver.java.
◆ reset()
|
inline |
Advanced usage: resets extracted model to solve from scratch.
This won't reset the parameters that were set with
SetSolverSpecificParametersAsString() or set_time_limit() or even clear the
linear program. It will just make sure that next Solve() will be as if
everything was reconstructed from scratch.
Definition at line 304 of file MPSolver.java.
◆ setHint()
|
inline |
Sets a hint for solution.
If a feasible or almost-feasible solution to the problem is already known,
it may be helpful to pass it to the solver so that it can be used. A
solver that supports this feature will try to use this information to
create its initial feasible solution.
Note that it may not always be faster to give a hint like this to the
solver. There is also no guarantee that the solver will use this hint or
try to return a solution "close" to this assignment in case of multiple
optimal solutions.
Definition at line 541 of file MPSolver.java.
◆ setNumThreads()
|
inline |
Sets the number of threads to be used by the solver.
Definition at line 548 of file MPSolver.java.
◆ setSolverSpecificParametersAsString()
|
inline |
Advanced usage: pass solver specific parameters in text format.
The format is solver-specific and is the same as the corresponding solver
configuration file format. Returns true if the operation was successful.
Definition at line 326 of file MPSolver.java.
◆ setTimeLimit()
|
inline |
Definition at line 397 of file MPSolver.java.
◆ solve() [1/2]
|
inline |
Solves the problem using the default parameter values.
Definition at line 253 of file MPSolver.java.
◆ solve() [2/2]
|
inline |
Solves the problem using the specified parameter values.
Definition at line 260 of file MPSolver.java.
◆ solveWithProto()
|
inlinestatic |
Solves the given model proto and returns a response proto.
Definition at line 487 of file MPSolver.java.
◆ supportsProblemType()
|
inlinestatic |
Whether the given problem type is supported (this will depend on the
targets that you linked).
Definition at line 103 of file MPSolver.java.
◆ suppressOutput()
|
inline |
Suppresses solver logging.
Definition at line 349 of file MPSolver.java.
◆ variables()
|
inline |
Returns the array of variables handled by the MPSolver.
(They are listed in
the order in which they were created.)
Definition at line 127 of file MPSolver.java.
◆ verifySolution()
|
inline |
Advanced usage: Verifies the correctness of the solution.
It verifies that all variables must be within their domains, all
constraints must be satisfied, and the reported objective value must be
accurate.
Usage:
- This can only be called after Solve() was called.
- "tolerance" is interpreted as an absolute error threshold.
- For the objective value only, if the absolute error is too large,
the tolerance is interpreted as a relative error threshold instead.
- If "log_errors" is true, every single violation will be logged.
- If "tolerance" is negative, it will be set to infinity().
Most users should just set the –verify_solution flag and not bother using
this method directly.
Definition at line 292 of file MPSolver.java.
◆ wallTime()
|
inline |
Definition at line 401 of file MPSolver.java.
The documentation for this class was generated from the following file: