Class Expression

An expression essentially is a tree which stores operators on subtrees which can either be Expressions or Terms themselves

Inheritance

System.Object

Expression

ConstantExpression

OperatorExpression

Term

Inherited Members

System.Object.ToString()

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

Namespace: OPTANO.Modeling.Optimization

Assembly: Optimization.dll

Syntax

[DataContract]
[Serializable]
public abstract class Expression

Fields

_bigMUserValue

Declaration

protected double? _bigMUserValue

Field Value

Type	Description
System.Nullable<System.Double>

Properties

BigM

Uses the (MRE) to automatically derive a BigM. If that fails, the user-provided fallback value for BigM is used.

Hint for user-provided value: BigM is used during the automatic transformation of OperatorExpressions into 'linear expressions' that can be handled by common MIP/LP solvers. Large number, only used if the bounds of the variables of the expressions are non-finite It should be chosen large enough, so that the solution space is not cut. But choosing this value too large, it can cause numerical errors.

Declaration

public double BigM { get; set; }

Property Value

Type	Description
System.Double

Exceptions

Type	Condition
System.InvalidOperationException	Thrown, if MRE evaluates to System.Double.IsInfinity(System.Double) and user did not provide a finite BigM estimation.

Constant

Gets the constant of this expression.

Declaration

public virtual double Constant { get; }

Property Value

Type	Description
System.Double	The constant.

ContainsAtMostOneVariable

Declaration

public abstract bool ContainsAtMostOneVariable { get; }

Property Value

Type	Description
System.Boolean

ContainsNoVariables

Declaration

public abstract bool ContainsNoVariables { get; }

Property Value

Type	Description
System.Boolean

EmptyExpression

Gets an empty Expression.

Declaration

public static Expression EmptyExpression { get; }

Property Value

Type	Description
Expression

IsLinear

Gets or sets a value indicating whether this instance is linear.

Declaration

public abstract bool IsLinear { get; }

Property Value

Type	Description
System.Boolean	true if this instance is linear; otherwise, false.

NonZeroTerms

Gets all terms with non-0 factors. Does not check if results are unique.

Declaration

protected IEnumerable<Term> NonZeroTerms { get; }

Property Value

Type	Description
System.Collections.Generic.IEnumerable<Term>

Terms

Gets a list of the terms in this expression. It does not contain any operators and does not tell you anything aobut how they are combined with operators.

Declaration

public abstract IEnumerable<Term> Terms { get; }

Property Value

Type	Description
System.Collections.Generic.IEnumerable<Term>	The terms.

Variables

Gets the variables in this expression.

Declaration

public abstract IEnumerable<Variable> Variables { get; }

Property Value

Type	Description
System.Collections.Generic.IEnumerable<Variable>	The variables.

Methods

Absolute(Expression, Nullable<Double>)

Creates an OperatorExpression that represents the absolute of the given expression.

Declaration

public static Abs Absolute(Expression expression, double? bigM = default(double? ))

Parameters

Type	Name	Description
Expression	expression	Expressions of which the absolute should be determined. Mustn't be null.
System.Nullable<System.Double>	bigM	Large number, only used if the bounds of the variables of the expressions are non-finite. It should be chosen large enough, so that the solution space is not cut. But choosing this value too large, it can cause numerical errors.

Returns

Type	Description
Abs	An Abs that represents |expression|.

Ceiling(Expression, Nullable<Double>)

Creates an OperatorExpression that represents the ceiling of the given expression.

Declaration

public static Ceil Ceiling(Expression expression, double? bigM = default(double? ))

Parameters

Type	Name	Description
Expression	expression	Expressions of which the ceiling should be determined. Mustn't be null.
System.Nullable<System.Double>	bigM	Large number, only used if the bounds of the variables of the expressions are non-finite. It should be chosen large enough, so that the solution space is not cut. But choosing this value too large, it can cause numerical errors.

Returns

Type	Description
Ceil	A Ceil expression that will be evaluated to the smallest integer greater or equal to the given expression.

Evaluate(IDictionary<String, Double>)

Evaluates the expression using the specified variable values.

Declaration

public double Evaluate(IDictionary<string, double> variableValues)

Parameters

Type	Name	Description
System.Collections.Generic.IDictionary<System.String, System.Double>	variableValues	The variable values.

Returns

Type	Description
System.Double	The result of the evaluation.

Floor(Expression, Nullable<Double>)

Creates an OperatorExpression that represents the floor of the given expression.

Declaration

public static Floor Floor(Expression expression, double? bigM = default(double? ))

Parameters

Type	Name	Description
Expression	expression	Expressions of which the floor should be determined. Mustn't be null.
System.Nullable<System.Double>	bigM	Large number, only used if the bounds of the variables of the expressions are non-finite. It should be chosen large enough, so that the solution space is not cut. But choosing this value too large, it can cause numerical errors.

Returns

Type	Description
Floor	A Floor(Expression, Nullable<Double>) expression that will be evaluated to the largest integer less or equal to the given expression.

Maximum(IEnumerable<Expression>, Nullable<Double>)

Creates an OperatorExpression that represents the Max over the given expressions.

Declaration

public static Max Maximum(IEnumerable<Expression> expressions, double? bigM = default(double? ))

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<Expression>	expressions	Expressions of which the maximum should be determined. Mustn't be null or empty.
System.Nullable<System.Double>	bigM	Large number, only used if the bounds of the variables of the expressions are non-finite. It should be chosen large enough, so that the solution space is not cut. But choosing this value too large, it can cause numerical errors.

Returns

Type	Description
Max	A Max OperatorExpression over the given expressions

Minimum(IEnumerable<Expression>, Nullable<Double>)

Creates an Expression that represents the Min over the given expressions.

Declaration

public static Min Minimum(IEnumerable<Expression> expressions, double? bigM = default(double? ))

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<Expression>	expressions	Expressions of which the minimum should be determined. Mustn't be null or empty.
System.Nullable<System.Double>	bigM	Large number, only used if the bounds of the variables of the expressions are non-finite. It should be chosen large enough, so that the solution space is not cut. But choosing this value too large, it can cause numerical errors.

Returns

Type	Description
Min	A Min OperatorExpression over the given expressions

Normalize()

Flattens the expression. Only works for linear expressions and the result is a sum of terms + a constant.

Declaration

public Expression Normalize()

Returns

Type	Description
Expression	The Expression.

Sum(IEnumerable<Expression>)

Sums the specified expressions.

Declaration

public static Expression Sum(IEnumerable<Expression> expressions)

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<Expression>	expressions	The expressions.

Returns

Type	Description
Expression	The Expression.

Sum(IEnumerable<Term>)

Sums the specified terms.

Declaration

public static Expression Sum(IEnumerable<Term> expressions)

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<Term>	expressions	The terms.

Returns

Type	Description
Expression	The Expression.

Sum(IEnumerable<Variable>)

Sums the specified variables.

Declaration

public static Expression Sum(IEnumerable<Variable> variables)

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<Variable>	variables	The variables.

Returns

Type	Description
Expression	The Expression.

Sum(IEnumerable<Double>)

Sums up the specified values.

Declaration

public static Expression Sum(IEnumerable<double> values)

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<System.Double>	values	The expressions.

Returns

Type	Description
Expression	The Expression.

Sum(Int32, Int32, Func<Int32, Expression>)

Sums the specified range of expressions.

Declaration

public static Expression Sum(int start, int count, Func<int, Expression> selector)

Parameters

Type	Name	Description
System.Int32	start	The start.
System.Int32	count	The count.
System.Func<System.Int32, Expression>	selector	The selector.

Returns

Type	Description
Expression	The Expression.

Sum(Int32, Int32, Func<Int32, Term>)

Sums the specified range of terms.

Declaration

public static Expression Sum(int start, int count, Func<int, Term> selector)

Parameters

Type	Name	Description
System.Int32	start	The start.
System.Int32	count	The count.
System.Func<System.Int32, Term>	selector	The selector.

Returns

Type	Description
Expression	The Expression.

Operators

Addition(Expression, Expression)

Implements the operator +.

Declaration

public static Expression operator +(Expression expression1, Expression expression2)

Parameters

Type	Name	Description
Expression	expression1	The first expression.
Expression	expression2	The second expression.

Returns

Type	Description
Expression	The result of the operator.

Addition(Expression, Variable)

Implements the operator +.

Declaration

public static Expression operator +(Expression expression1, Variable variable)

Parameters

Type	Name	Description
Expression	expression1	The expression.
Variable	variable	The variable.

Returns

Type	Description
Expression	The result of the operator.

Addition(Expression, Double)

Adds a constant to an expression

Declaration

public static Expression operator +(Expression expression, double constant)

Parameters

Type	Name	Description
Expression	expression
System.Double	constant

Returns

Type	Description
Expression

Addition(Variable, Expression)

Implements the operator +.

Declaration

public static Expression operator +(Variable variable, Expression expression1)

Parameters

Type	Name	Description
Variable	variable	The variable.
Expression	expression1	The expression.

Returns

Type	Description
Expression	The result of the operator.

Addition(Double, Expression)

Adds a constant to an expression

Declaration

public static Expression operator +(double constant, Expression expression)

Parameters

Type	Name	Description
System.Double	constant
Expression	expression

Returns

Type	Description
Expression

Division(Expression, Double)

Implements the operator /.

Declaration

public static Expression operator /(Expression expression, double constant)

Parameters

Type	Name	Description
Expression	expression	The expression.
System.Double	constant	The constant.

Returns

Type	Description
Expression	The result of the operator.

Equality(Expression, Expression)

Implements the operator ==.

Declaration

public static Constraint operator ==(Expression expression1, Expression expression2)

Parameters

Type	Name	Description
Expression	expression1	The first expression.
Expression	expression2	The second expression.

Returns

Type	Description
Constraint	The result of the operator.

Equality(Expression, Variable)

Implements the operator '=='.

Declaration

public static Constraint operator ==(Expression expression, Variable variable)

Parameters

Type	Name	Description
Expression	expression	The expression.
Variable	variable	The variable.

Returns

Type	Description
Constraint	A Constraint where expression == variable.

Exceptions

Type	Condition
System.ArgumentNullException	Arguments mustn't be null.

Equality(Expression, Double)

Implements the operator ==.

Declaration

public static Constraint operator ==(Expression expression, double value)

Parameters

Type	Name	Description
Expression	expression	The expression.
System.Double	value	The constant.

Returns

Type	Description
Constraint	The result of the operator.

Equality(Variable, Expression)

Creates a new equality constraint

Declaration

public static Constraint operator ==(Variable variable, Expression expression)

Parameters

Type	Name	Description
Variable	variable	The variable.
Expression	expression	The expression.

Returns

Type	Description
Constraint	The a new constraint as the result of the operator.

Equality(Double, Expression)

Implements the operator ==.

Declaration

public static Constraint operator ==(double value, Expression expression)

Parameters

Type	Name	Description
System.Double	value	The constant.
Expression	expression	The expression.

Returns

Type	Description
Constraint	The result of the operator.

GreaterThanOrEqual(Expression, Expression)

Implements the operator >=.

Declaration

public static Constraint operator >=(Expression expression1, Expression expression2)

Parameters

Type	Name	Description
Expression	expression1	The first expression.
Expression	expression2	The second expression.

Returns

Type	Description
Constraint	The result of the operator.

GreaterThanOrEqual(Expression, Variable)

Implements the operator >=.

Declaration

public static Constraint operator >=(Expression expression, Variable variable)

Parameters

Type	Name	Description
Expression	expression	The expression.
Variable	variable	The variable.

Returns

Type	Description
Constraint	The result of the operator.

GreaterThanOrEqual(Expression, Double)

Implements the operator >=.

Declaration

public static Constraint operator >=(Expression expression, double constant)

Parameters

Type	Name	Description
Expression	expression	The expression.
System.Double	constant	The constant.

Returns

Type	Description
Constraint	The result of the operator.

GreaterThanOrEqual(Variable, Expression)

Implements the operator >=.

Declaration

public static Constraint operator >=(Variable variable, Expression expression)

Parameters

Type	Name	Description
Variable	variable	The variable.
Expression	expression	The expression.

Returns

Type	Description
Constraint	The result of the operator.

GreaterThanOrEqual(Double, Expression)

Implements the operator >=.

Declaration

public static Constraint operator >=(double constant, Expression expression)

Parameters

Type	Name	Description
System.Double	constant	The constant.
Expression	expression	The expression.

Returns

Type	Description
Constraint	The result of the operator.

Implicit(Variable to Expression)

Implicit conversion from Variable to Expression.

Declaration

public static implicit operator Expression(Variable variable)

Parameters

Type	Name	Description
Variable	variable	The variable to convert.

Returns

Type	Description
Expression	A new Term that contains the variable, casted as a general Expression.

Inequality(Expression, Expression)

Please construct inequalities using <= and >=

Declaration

public static Constraint operator !=(Expression expression, Expression expression2)

Parameters

Type	Name	Description
Expression	expression	The expression.
Expression	expression2	The expression2.

Returns

Type	Description
Constraint	The result of the operator.

Inequality(Expression, Variable)

Please construct inequalities using <= and >=

Declaration

public static Constraint operator !=(Expression expression, Variable variable)

Parameters

Type	Name	Description
Expression	expression	The expression.
Variable	variable	The variable.

Returns

Type	Description
Constraint	The result of the operator.

Inequality(Expression, Double)

Please construct inequalities using <= and >=

Declaration

public static Constraint operator !=(Expression expression, double value)

Parameters

Type	Name	Description
Expression	expression	The expression.
System.Double	value	The value.

Returns

Type	Description
Constraint	The result of the operator.

Inequality(Variable, Expression)

Please construct inequalities using <= and >=

Declaration

public static Constraint operator !=(Variable variable, Expression expression)

Parameters

Type	Name	Description
Variable	variable	The variable.
Expression	expression	The expression.

Returns

Type	Description
Constraint	The result of the operator.

Inequality(Double, Expression)

Please construct inequalities using <= and >=

Declaration

public static Constraint operator !=(double value, Expression expression)

Parameters

Type	Name	Description
System.Double	value	The value.
Expression	expression	The expression.

Returns

Type	Description
Constraint	The result of the operator.

LessThanOrEqual(Expression, Expression)

Implements the operator <=.

Declaration

public static Constraint operator <=(Expression expression1, Expression expression2)

Parameters

Type	Name	Description
Expression	expression1	The first expression.
Expression	expression2	The second expression.

Returns

Type	Description
Constraint	The result of the operator.

LessThanOrEqual(Expression, Variable)

Implements the operator <=.

Declaration

public static Constraint operator <=(Expression expression, Variable variable)

Parameters

Type	Name	Description
Expression	expression	The expression.
Variable	variable	The variable.

Returns

Type	Description
Constraint	The result of the operator.

LessThanOrEqual(Expression, Double)

Implements the operator <=.

Declaration

public static Constraint operator <=(Expression expression, double constant)

Parameters

Type	Name	Description
Expression	expression	The expression.
System.Double	constant	The constant.

Returns

Type	Description
Constraint	The result of the operator.

LessThanOrEqual(Variable, Expression)

Implements the operator <=.

Declaration

public static Constraint operator <=(Variable variable, Expression expression)

Parameters

Type	Name	Description
Variable	variable	The variable.
Expression	expression	The expression.

Returns

Type	Description
Constraint	The result of the operator.

LessThanOrEqual(Double, Expression)

Implements the operator <=.

Declaration

public static Constraint operator <=(double constant, Expression expression)

Parameters

Type	Name	Description
System.Double	constant	The constant.
Expression	expression	The expression.

Returns

Type	Description
Constraint	The result of the operator.

Multiply(Expression, Expression)

Implements the operator *.

Declaration

public static Expression operator *(Expression expression, Expression expression2)

Parameters

Type	Name	Description
Expression	expression	The first expression.
Expression	expression2	The second expression.

Returns

Type	Description
Expression	The result of the operator.

Multiply(Expression, Variable)

Implements the operator *.

Declaration

public static Expression operator *(Expression expression, Variable variable)

Parameters

Type	Name	Description
Expression	expression	The expression.
Variable	variable	The variable.

Returns

Type	Description
Expression	The result of the operator.

Multiply(Expression, Double)

Implements the operator *.

Declaration

public static Expression operator *(Expression expression, double constant)

Parameters

Type	Name	Description
Expression	expression	The expression.
System.Double	constant	The constant.

Returns

Type	Description
Expression	The result of the operator.

Multiply(Double, Expression)

Implements the operator *.

Declaration

public static Expression operator *(double constant, Expression expression)

Parameters

Type	Name	Description
System.Double	constant	The constant.
Expression	expression	The expression.

Returns

Type	Description
Expression	The result of the operator.

Subtraction(Expression, Expression)

Implements the operator -.

Declaration

public static Expression operator -(Expression expression1, Expression expression2)

Parameters

Type	Name	Description
Expression	expression1	The first expression.
Expression	expression2	The second expression.

Returns

Type	Description
Expression	The result of the operator.

Subtraction(Expression, Variable)

Implements the operator -.

Declaration

public static Expression operator -(Expression expression, Variable variable)

Parameters

Type	Name	Description
Expression	expression	The expression.
Variable	variable	The variable.

Returns

Type	Description
Expression	The result of the operator.

Subtraction(Expression, Double)

Implements the operator -.

Declaration

public static Expression operator -(Expression expression1, double constant)

Parameters

Type	Name	Description
Expression	expression1	The expression.
System.Double	constant	The constant.

Returns

Type	Description
Expression	The result of the operator.

Subtraction(Variable, Expression)

Implements the operator -.

Declaration

public static Expression operator -(Variable variable, Expression expression)

Parameters

Type	Name	Description
Variable	variable	The variable.
Expression	expression	The expression.

Returns

Type	Description
Expression	The result of the operator.

Subtraction(Double, Expression)

Implements the operator -.

Declaration

public static Expression operator -(double constant, Expression expression1)

Parameters

Type	Name	Description
System.Double	constant	The constant.
Expression	expression1	The expression1.

Returns

Type	Description
Expression	The result of the operator.

Extension Methods

ReflectionHelper.GetFieldValue(Object, String)

ReflectionHelper.SetFieldValue(Object, String, Object)

ExtensionMethods.Clone<T>(T)

ExtensionMethods.ThrowIfArgumentIsNull<T>(T, String)