# LSSolution Class¶

class localsolver.LSSolution

Solution to the optimization model. A solution carries the values of all expressions in the model. It is used to retrieve the values of all expressions (getting the solution), or to set the values of some decisions (setting the solution).

See

LSSolutionStatus

## Summary¶

 GetLocalSolver Returns the LocalSolver object associated to this solution. SetValue Sets the value of the given expression in this solution. SetIntValue Sets the value of the given expression in this solution. SetDoubleValue Sets the value of the given expression in this solution. GetValue Returns the value of the given expression in this solution. GetDoubleValue Returns the value of the given expression in this solution. GetIntValue Returns the value of the given expression in this solution. GetCollectionValue Returns the value of the given expression in this solution. GetArrayValue Returns the value of the given expression in this solution. IsViolated Returns true if the given expression is violated in this solution. IsUndefined Returns true if the given expression has an undefined value in this solution. GetStatus Returns the status of the solution. GetObjectiveBound Returns the bound computed by the solver for the given objective. GetIntObjectiveBound Returns the bound computed by the solver for the given objective. GetDoubleObjectiveBound Returns the bound computed by the solver for the given objective. GetObjectiveGap Returns the gap computed by the solver for the given objective. Clear Clear the solution and set all decisions to zero.

## Instance methods¶

LocalSolver GetLocalSolver()

Returns the LocalSolver object associated to this solution.

Returns

LocalSolver object

Return type

LocalSolver

void SetValue(LSExpression expr, long value)

Sets the value of the given expression in this solution. Only decisions can be set. Only allowed in state Stopped. Only allowed if this expression is an integer or a boolean. If the solver was not launched, this value will be used as an initial value for the decision.

This method has the same behavior as LSSolution.SetIntValue.

Arguments
• expr (LSExpression) – Decision.

• value (long) – Value assigned to the decision in this solution.

See

LSExpression.IsDecision

See

LSExpression.IsInt

See

LSExpression.IsBool

void SetValue(LSExpression expr, double value)

Sets the value of the given expression in this solution. Only decisions can be set. Only allowed in state Stopped. Only allowed if this expression is a double. If the solver was not launched, this value will be used as an initial value for the decision.

This method has the same behavior as LSSolution.SetDoubleValue.

Arguments
• expr (LSExpression) – Decision.

• value (double) – Value assigned to the decision in this solution.

See

LSExpression.IsDecision

See

LSExpression.IsDouble

void SetIntValue(LSExpression expr, long value)

Sets the value of the given expression in this solution. Only decisions can be set. Only allowed in state Stopped. Only allowed if this expression is an integer or a boolean. If the solver was not launched, this value will be used as an initial value for the decision.

Since

3.0

Arguments
• expr (LSExpression) – Decision.

• value (long) – Value assigned to the decision in this solution.

See

LSExpression.IsDecision

See

LSExpression.IsInt

See

LSExpression.IsBool

void SetDoubleValue(LSExpression expr, long value)

Sets the value of the given expression in this solution. Only decisions can be set. Only allowed in state Stopped. If the solver was not launched, this value will be used as an initial value for the decision. Only allowed if this expression is a double.

Since

3.0

Arguments
• expr (LSExpression) – Decision.

• value (long) – Value assigned to the decision in this solution.

See

LSExpression.IsDecision

See

LSExpression.IsDouble

long GetValue(LSExpression expr)

Returns the value of the given expression in this solution. Only allowed in states Paused or Stopped. Only allowed if this expression is an integer or a boolean.

This method has the same behavior as LSSolution.GetIntValue.

Arguments

expr (LSExpression) – Expression.

Returns

Value of the expression in this solution.

Return type

long

See

LSExpression.IsInt

See

LSExpression.IsBool

double GetDoubleValue(LSExpression expr)

Returns the value of the given expression in this solution. Only allowed in states Paused or Stopped. Only allowed if this expression is a double.

Since

3.0

Arguments

expr (LSExpression) – Expression.

Returns

Value of the expression in this solution.

Return type

double

See

LSExpression.IsDouble

long GetIntValue(LSExpression expr)

Returns the value of the given expression in this solution. Only allowed in states Paused or Stopped. Only allowed if this expression is an integer or a boolean.

Since

3.0

Arguments

expr (LSExpression) – Expression.

Returns

Value of the expression in this solution.

Return type

long

See

LSExpression.IsInt

See

LSExpression.IsBool

LSCollection GetCollectionValue(LSExpression expr)

Returns the value of the given expression in this solution. Only allowed in states Paused or Stopped. Only allowed if this expression is a collection (list or set).

Since

5.5

Arguments

expr (LSExpression) – Expression.

Returns

Value of the expression in this solution.

Return type

LSCollection

See

LSExpression.IsCollection

LSCollection GetArrayValue(LSExpression expr)

Returns the value of the given expression in this solution. Only allowed in states Paused or Stopped. Only allowed if this expression is an array.

Since

7.5

Arguments

expr (LSExpression) – Expression.

Returns

Value of the expression in this solution.

Return type

LSArray

See

LSExpression.IsArray

bool IsViolated(LSExpression expr)

Returns true if the given expression is violated in this solution. An expression can be violated in 3 cases:

• It is a constraint and its value is 0.

• It is a a double and its value is NaN (Not A Number).

• It is an integer or boolean with no valid value (arithmetic or out of bounds exception).

Only allowed in states Paused or Stopped.

Since

5.5

Arguments

expr (LSExpression) – Expression.

Returns

True if the expression is violated in this solution.

Return type

bool

bool IsUndefined(LSExpression expr)

Returns true if the given expression has an undefined value in this solution. An expression can be undefined in 2 cases:

• It is a a double and its value is NaN (NotANumber).

• It is an integer or boolean with no valid value (arithmetic or out of bounds exception).

Only allowed in states Paused or Stopped.

Since

7.0

Arguments

expr (LSExpression) – Expression.

Returns

True if this expression has an undefined value in this solution.

LSSolutionStatus GetStatus()

Returns the status of the solution. Only allowed in states Paused or Stopped.

Returns

Status of the solution

Return type

LSSolutionStatus

long GetObjectiveBound(int objectiveIndex)

Returns the bound computed by the solver for the given objective. If the solver has never been launched, this method returns Int64.MaxValue or Int64.MinValue depending on the optimization direction of the objective. Only allowed in states Paused or Stopped. Only allowed if this expression is a boolean or an integer. This method has the same behavior as LSSolution.GetIntObjectiveBound.

Since

8.5

Arguments

objectiveIndex (int) – Index of the objective.

Returns

Bound of the given objective.

Return type

long

See

LSExpression.IsInt

See

LSExpression.IsBool

long GetIntObjectiveBound(int objectiveIndex)

Returns the bound computed by the solver for the given objective. If the solver has never been launched, this method returns Int64.MaxValue or Int64.MinValue depending on the optimization direction of the objective. Only allowed in states Paused or Stopped. Only allowed if this expression is a boolean or an integer.

Since

8.5

Arguments

objectiveIndex (int) – Index of the objective.

Returns

Bound of the given objective.

Return type

long

See

LSExpression.IsInt

See

LSExpression.IsBool

double GetDoubleObjectiveBound(int objectiveIndex)

Returns the bound computed by the solver for the given objective. If the solver has never been launched, this method returns Double.PositiveInfinity or Double.NegativeInfinity depending on the optimization direction of the objective. Only allowed in states Paused or Stopped. Only allowed if this expression is a double.

Since

8.5

Arguments

objectiveIndex (int) – Index of the objective.

Returns

Bound of the given objective.

Return type

double

See

LSExpression.IsDouble

double GetObjectiveGap(int objectiveIndex)

Returns the gap computed by the solver for the given objective. It is defined as:

$|obj - bound| / \max(1, |obj|, |bound|)$

Only allowed in states Paused or Stopped.

Arguments

objectiveIndex (int) – Index of the objective.

Returns

Gap of the given objective.

Return type

double

void Clear()

Clear the solution and set all decisions to zero. Only allowed in state Stopped.