org.ojalgo.optimisation

Class Presolvers

java.lang.Object

org.ojalgo.optimisation.Presolvers

public abstract class Presolvers
extends Object

Field Summary

Fields

Modifier and Type	Field and Description
static ExpressionsBasedModel.Presolver	BINARY_VALUE If an expression contains at least 1 binary variable and all non-fixed variable weights are of the same sign (positive or negative) then it is possible the check the validity of "1" for each of the binary variables.
static org.ojalgo.optimisation.ExpressionsBasedModel.VariableAnalyser	FIXED_OR_UNBOUNDED Verifies that the variable is actually referenced/used in some expression.
static ExpressionsBasedModel.Presolver	LINEAR_OBJECTIVE If the expression is linear and contributes to the objective function, then the contributions are transferred to the variables and the weight of the expression set to null.
static ExpressionsBasedModel.Presolver	OPPOSITE_SIGN Checks the sign of the limits and the sign of the expression parameters to deduce variables that in fact can only be zero.
static ExpressionsBasedModel.Presolver	ZERO_ONE_TWO Looks for constraint expressions with 0, 1 or 2 non-fixed variables.

Constructor Summary

Constructors

Constructor and Description
Presolvers()

Method Summary

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

BINARY_VALUE

public static final ExpressionsBasedModel.Presolver BINARY_VALUE

If an expression contains at least 1 binary variable and all non-fixed variable weights are of the same sign (positive or negative) then it is possible the check the validity of "1" for each of the binary variables. (Doesn't seem to work and/or is not effective.)

FIXED_OR_UNBOUNDED

public static final org.ojalgo.optimisation.ExpressionsBasedModel.VariableAnalyser FIXED_OR_UNBOUNDED

Verifies that the variable is actually referenced/used in some expression. If not then that variable can either be fixed or marked as unbounded. Also makes sure integer variables have integer lower/upper bounds (if they exist).

LINEAR_OBJECTIVE

public static final ExpressionsBasedModel.Presolver LINEAR_OBJECTIVE

If the expression is linear and contributes to the objective function, then the contributions are transferred to the variables and the weight of the expression set to null.

OPPOSITE_SIGN

public static final ExpressionsBasedModel.Presolver OPPOSITE_SIGN

Checks the sign of the limits and the sign of the expression parameters to deduce variables that in fact can only be zero.

ZERO_ONE_TWO

public static final ExpressionsBasedModel.Presolver ZERO_ONE_TWO

Looks for constraint expressions with 0, 1 or 2 non-fixed variables. Transfers the constraints of the expressions to the variables and then (if possible) marks the expression as redundant.

Constructor Detail

Presolvers

public Presolvers()