Class MathExpression

Simple math expression parser and evaluator

Inheritance

object

MathExpression

Namespace: ABB.Robotics.Math

Assembly: ABB.Robotics.Math.dll

Syntax

public class MathExpression

Remarks

Literal values should be using '.' as a decimal separator.

Constructors

MathExpression(double)

Creates a simple MathExpression from the given value

Declaration

public MathExpression(double val)

Parameters

Type	Name	Description
double	val	Value to build expression for

Remarks

Calling Evaluate() will return the given value

MathExpression(double, int)

Creates a simple MathExpression from the given value with the specified number of decimals

Declaration

public MathExpression(double val, int numDecimals)

Parameters

Type	Name	Description
double	val	Value to build expression for
int	numDecimals	Maximum number of decimals to use

Remarks

Calling Evaluate() will return the given value (rounded to the given number of decimals).

MathExpression(string)

Creates a new MathExpression class from a mathematical expression

Declaration

public MathExpression(string expression)

Parameters

Type	Name	Description
string	expression

MathExpression(string, bool)

Creates a new MathExpression class from a mathematical expression, optionally converting arguments of trigonometric functions from degrees

Declaration

public MathExpression(string expression, bool convertDegrees)

Parameters

Type	Name	Description
string	expression	The mathematical expression
bool	convertDegrees	If true convert the arguments of trigonometric functions from degrees to radians

Properties

ErrorText

If the expression is invalid (IsValid returns false), this property may return more information why.

Declaration

public string ErrorText { get; }

Property Value

Type	Description
string

ExpressionString

Gets or sets the source expression string

Declaration

public string ExpressionString { get; set; }

Property Value

Type	Description
string

IsSimple

Returns True if the expression consists of a single value

Declaration

public bool IsSimple { get; }

Property Value

Type	Description
bool

IsValid

Returns True if the expression is valid and can be evaluated

Declaration

public bool IsValid { get; }

Property Value

Type	Description
bool

VariableNames

Returns the names of variables used in the expression

Declaration

public IEnumerable<string> VariableNames { get; }

Property Value

Type	Description
IEnumerable<string>

Methods

Evaluate()

Evaluates the expression

Declaration

public double Evaluate()

Returns

Type	Description
double	The evaluated value of the expression

Evaluate(IDictionary<string, double>)

Evaluates the expression, using the passed in dictionary of variable values

Declaration

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

Parameters

Type	Name	Description
IDictionary<string, double>	variableValues

Returns

Type	Description
double?	The evaluated value of the expression

Remarks

This overload is thread-safe, as long as no other methods on this class are called concurrently.

GetAllowedOperators()

Returns the allowed operators

Declaration

public static string[] GetAllowedOperators()

Returns

Type	Description
string[]

GetLinearCoefficients(string[])

Returns the linear coefficients, if this expression is linear in the set of given variables. Otherwise it returns null.

Declaration

public double[] GetLinearCoefficients(string[] variables)

Parameters

Type	Name	Description
string[]	variables

Returns

Type	Description
double[]

SetVariableValue(string, double)

Sets the value of a variable, which will be used the next time the expression is evaluated.

Declaration

public void SetVariableValue(string variable, double val)

Parameters

Type	Name	Description
string	variable	Name of the variable to set
double	val	New value of the variable

TrySetVariableValue(string, double)

Sets the value of a variable, which will be used the next time the expression is evaluated.

Declaration

public bool TrySetVariableValue(string variable, double val)

Parameters

Type	Name	Description
string	variable	Name of the variable to set
double	val	New value of the variable

Returns

Type	Description
bool	True if the variable could be set (i.e. if it exists), false otherwise