MathEvaluator 2.1.0

There is a newer version of this package available.
See the version list below for details.
dotnet add package MathEvaluator --version 2.1.0                
NuGet\Install-Package MathEvaluator -Version 2.1.0                
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="MathEvaluator" Version="2.1.0" />                
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add MathEvaluator --version 2.1.0                
#r "nuget: MathEvaluator, 2.1.0"                
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install MathEvaluator as a Cake Addin
#addin nuget:?package=MathEvaluator&version=2.1.0

// Install MathEvaluator as a Cake Tool
#tool nuget:?package=MathEvaluator&version=2.1.0                

Math Expression Evaluator in .NET

NuGet Downloads NuGet Version

Overview

MathEvaluator is a .NET library that allows you to evaluate and compile any mathematical expressions from a string dynamically.

Features

  • Supports different mathematical contexts, such as scientific, programming, and other custom contexts.
  • Evaluates to double, boolean, or decimal.
  • Compiles a math expression string into executable code and produces a delegate that represents the math expression.
  • Provides variable support within math expressions.
  • Extensible with custom functions and operators.
  • Fast and comprehensive. More than 1300 tests are passed, including complex math expressions (for example, -3^4sin(-π/2) or sin-3/cos1).

Articles

Evaluating Boolean logical expressions.

Compilation of a Math Expression into a delegate.

Installation

dotnet add package MathEvaluator

Alternatively, you can install the package using the NuGet Package Manager Console:

Install-Package MathEvaluator

Perfomance

This math expression evaluator is designed for exceptional performance by leveraging modern .NET features and best practices, which is why it targets .NET Standard 2.1 or higher.

This high-performance evaluator stands out due to its use of ReadOnlySpan<char>, and avoidance of regular expressions. These design choices collectively ensure minimal memory allocation, fast parsing, and efficient execution.

The evaluator uses recursive method calls to handle mathematical operations based on operator precedence and rules, an operator with highest precedence is evaluating first. This approach avoids the overhead associated with stack or queue data structures.

The evaluator uses a prefix tree, also known as a trie (pronounced "try"), for efficient searching of variables, operators, and functions by their keys (names) when providing a specific mathematical context or adding custom variables, operators, and functions is required.

Let's compare, for example, performance of calculating the mathematical expression:

22888.32 * 30 / 323.34 / .5 - -1 / (2 + 22888.32) * 4 - 6

Below are the results of the comparison with the NCalc library:

Method Job Runtime Mean Error StdDev Gen0 Allocated
MathEvaluator .NET 6.0 .NET 6.0 654.5 ns 2.09 ns 1.63 ns 0.0067 88 B
NCalc .NET 6.0 .NET 6.0 8,408.6 ns 42.70 ns 39.94 ns 0.3967 5160 B
MathEvaluator .NET 8.0 .NET 8.0 589.9 ns 2.58 ns 2.41 ns 0.0067 88 B
NCalc .NET 8.0 .NET 8.0 6,184.0 ns 30.74 ns 28.75 ns 0.3510 4472 B

NOTE: NCalc includes built-in caching, enabled by default in recent versions. While this can improve benchmark performance, in real-world scenarios, caching may increase memory usage and is not effective if the evaluation results depend on variable values. In such cases, compilation is a better alternative.

Compilation

Added in version 2.0.0

By using compilation, you can convert any mathematical expression string into a delegate, such as Func<T, TResult> or Func<TResult>, which significantly improves performance when evaluating the expression. However, since compilation takes time, it is beneficial to compile the expression beforehand if you plan to evaluate it multiple times, especially for 200 or more iterations. Refer to the benchmarks for detailed performance insights.

How to use

Examples of using string extentions:

"22888.32 * 30 / 323.34 / .5 - -1 / (2 + 22888.32) * 4 - 6".Evaluate();

"22888.32 * 30 / 323.34 / .5 - -1 / (2 + 22888.32) * 4 - 6".EvaluateDecimal();

"$22,888.32 * 30 / 323.34 / .5 - - 1 / (2 + $22,888.32) * 4 - 6".Evaluate(null, new CultureInfo("en-US"));

"22’888.32 CHF * 30 / 323.34 / .5 - - 1 / (2 + 22’888.32 CHF) * 4 - 6".EvaluateDecimal(null, new CultureInfo("de-CH"));

"ln(1/-0.5 + √(1/(0.5^2) + 1))".Evaluate(new ScientificMathContext());

"ln(1/-0,5 + √(1/(0,5^2) + 1))".Evaluate(new ScientificMathContext(), new CultureInfo("fr"));

"ln(1/-0.5 + √(1/(0.5^2) + 1))".EvaluateDecimal(new DecimalScientificMathContext());

"ln(1/-0,5 + √(1/(0,5^2) + 1))".EvaluateDecimal(new DecimalScientificMathContext(), new CultureInfo("fr"));

"4 % 3".Evaluate(new ProgrammingMathContext());

"4 mod 3".EvaluateDecimal(new DecimalScientificMathContext());

"4 <> 4 OR 5.4 = 5.4 AND NOT 0 < 1 XOR 1.0 - 1.95 * 2 >= -12.9 + 0.1 / 0.01".EvaluateBoolean(new ProgrammingMathContext());

"¬⊥∧⊤∨¬⊤⇒¬⊤".EvaluateBoolean(new ScientificMathContext());

Examples of using an instance of the MathExpression class:

new MathExpression("22888.32 * 30 / 323.34 / .5 - -1 / (2 + 22888.32) * 4 - 6").Evaluate();

new MathExpression("22888.32 * 30 / 323.34 / .5 - -1 / (2 + 22888.32) * 4 - 6").EvaluateDecimal();

new MathExpression("$22,888.32 * 30 / 323.34 / .5 - - 1 / (2 + $22,888.32) * 4 - 6", null, new CultureInfo("en-US")).Evaluate();

new MathExpression("22’888.32 CHF * 30 / 323.34 / .5 - - 1 / (2 + 22’888.32 CHF) * 4 - 6", null, new CultureInfo("de-CH")).EvaluateDecimal();

new MathExpression("ln(1/-0.5 + √(1/(0.5^2) + 1))", new ScientificMathContext()).Evaluate();

new MathExpression("ln(1/-0,5 + √(1/(0,5^2) + 1))", new ScientificMathContext(), new CultureInfo("fr")).Evaluate();

new MathExpression("ln(1/-0.5 + √(1/(0.5^2) + 1))", new DecimalScientificMathContext()).EvaluateDecimal();

new MathExpression("ln(1/-0,5 + √(1/(0,5^2) + 1))", new DecimalScientificMathContext(), new CultureInfo("fr")).EvaluateDecimal();

new MathExpression("4 % 3", new ProgrammingMathContext()).Evaluate();

new MathExpression("4 mod 3", new DecimalScientificMathContext()).EvaluateDecimal();

new MathExpression("4 <> 4 OR 5.4 = 5.4 AND NOT 0 < 1 XOR 1.0 - 1.95 * 2 >= -12.9 + 0.1 / 0.01", new ProgrammingMathContext()).EvaluateBoolean();

new MathExpression("¬⊥∧⊤∨¬⊤⇒¬⊤", new ScientificMathContext()).EvaluateBoolean();

Examples of passing custom variables and functions as parameters:

var x1 = 0.5;
var x2 = -0.5;
var sqrt = Math.Sqrt;
Func<double, double> ln = Math.Log;

var value1 = "ln(1/-x1 + sqrt(1/(x2*x2) + 1))"
    .Evaluate(new { x1, x2, sqrt, ln });

var parameters = new MathParameters();
parameters.BindVariable(0.5, "x1");
parameters.BindVariable(-0.5, "x2");
parameters.BindFunction(Math.Sqrt);
parameters.BindFunction(d => Math.Log(d), "ln");

var value2 = "ln(1/-x1 + Math.Sqrt(1/(x2*x2) + 1))"
    .Evaluate(parameters);

Example of using custom context:

var context = new MathContext();
context.BindFunction(Math.Sqrt);
context.BindFunction(d => Math.Log(d), "ln");

"ln(1/-x1 + Math.Sqrt(1/(x2*x2) + 1))"
    .Evaluate(new { x1 = 0.5, x2 = -0.5 }, context);

Examples of compilation:

Func<decimal> fn1 = "22’888.32 CHF * 30 / 323.34 / .5 - - 1 / (2 + 22’888.32 CHF) * 4 - 6"
    .CompileDecimal(null, new CultureInfo("de-CH"));

var value1 = fn1();

var fn2 = "ln(1/x1 + √(1/(x2*x2) + 1))"
    .Compile(new { x1 = 0.0, x2 = 0.0 }, new ScientificMathContext());

var value2 = fn2(new { x1 = -0.5, x2 = 0.5 });

How to debug or log

Added in version 2.1.0

By using the Evaluating event, you can debug or log the steps of a math expression's evaluation. This event is triggered at each step during the evaluation process. The following code demonstrates how to use to this event:

using var expression = new MathExpression("-3^4sin(-PI/2)", new ScientificMathContext());
expression.Evaluating += (object? sender, EvaluatingEventArgs args) =>
{
    Console.WriteLine("{0}: {1} = {2};{3}",
        args.Step,
        args.MathString[args.Start..(args.End + 1)],
        args.Value,
        args.IsCompleted ? " //completed" : string.Empty);
};

var value = expression.Evaluate();

Output:

1: 3^4 = 81;
2: PI = 3.141592653589793;
3: PI/2 = 1.5707963267948966;
4: -PI/2 = -1.5707963267948966;
5: sin(-PI/2) = -1;
6: 3^4sin(-PI/2) = -81;
7: -3^4sin(-PI/2) = 81; //completed

NOTE: The Evaluating event is cleaned up in the Dispose method. I recommend using the using statement to ensure proper disposal and prevent memory leaks.

Supported math functions, operators, and constants

When no mathematical context is specified:
Notation Precedence
Addition + 0
Subtraction, Negativity - 0
Multiplication * 100
Division / 100
Parentheses ( ) 200
Currency symbol depends on culture info
Programming Math Context (using ProgrammingMathContext class):
Notation Precedence
Addition + 0
Subtraction, Negativity - 0
Multiplication * 100
Division / 100
Parentheses ( ) 200
Currency symbol depends on culture info
Exponentiation ** 400
Modulus % 100
Floor Division // 100
Logical constants true, false, True, False, TRUE, FALSE 300
Equality = -100
Inequality <> -100
Less than < -100
Greater than > -100
Less than or equal <= -100
Greater than or equal >= -100
Logical negation not, Not, NOT -200
Logical AND and, And, AND -300
Logical exclusive OR xor, Xor, XOR -400
Logical OR or, Or, OR -500
Scientific Math Context (using ScientificMathContext class):
Notation Precedence
Addition + 0
Subtraction, Negativity - 0
Multiplication *, ×, or · 100
Division / or ÷ 100
Parentheses ( ) 200
Currency symbol depends on culture info
Exponentiation ^ 400
Modulus mod, Mod, MOD, modulo, Modulo, or MODULO 100
Floor Division // 100
Absolute | |, abs, Abs, ABS 200
Ceiling ⌈ ⌉ 200
Floor ⌊ ⌋ 200
Square root, cube root, fourth root √, ∛, ∜ 200
Natural logarithmic base e 300
Natural logarithm ln, Ln, LN 200
Common logarithm (base 10) log, Log, LOG 200
Factorial ! 500
Infinity 300
Logical constants true, false, True, False, TRUE, FALSE, T, F, ⊤, ⊥ 300
Equality = -100
Inequality -100
Less than < -100
Greater than > -100
Less than or equal ≤, ⪯ -100
Greater than or equal ≥, ⪰ -100
Logical negation ¬, not, Not, NOT 500 for ¬, -200
Logical AND ∧, and, And, AND -300
Logical exclusive OR ⊕, xor, Xor, XOR -400
Logical OR ∨, or, Or, OR -500
Logical implication →, ⇒, ←, ⟸ -800
Logical biconditional equivalence ↔, ⇔ -900
Logical biconditional inequivalence ↮, ⇎ -900
Logical equivalence -1000
Logical inequivalence -1000
Degree ° 500
Pi constant π, pi, Pi, PI 300
Tau constant τ 300
Sine sin, Sin, SIN 200
Cosine cos, Cos, COS 200
Tangent tan, Tan, TAN 200
Secant sec, Sec, SEC 200
Cosecant csc, Csc, CSC 200
Cotangent cot, Cot, COT 200
Hyperbolic sine sinh, Sinh, SINH 200
Hyperbolic cosine cosh, Cosh, COSH 200
Hyperbolic tangent tanh, Tanh, TANH 200
Hyperbolic secant sech, Sech, SECH 200
Hyperbolic cosecant csch, Csch, CSCH 200
Hyperbolic cotangent coth, Coth, COTH 200
Inverse sine arcsin, Arcsin, ARCSIN, sin^-1, Sin^-1, SIN^-1 200
Inverse cosine arccos, Arccos, ARCCOS, cos^-1, Cos^-1, COS^-1 200
Inverse tangent arctan, Arctan, ARCTAN, tan^-1, Tan^-1, TAN^-1 200
Inverse secant arcsec, Arcsec, ARCSEC, sec^-1, Sec^-1, SEC^-1 200
Inverse cosecant arccsc, Arccsc, ARCCSC, csc^-1, Csc^-1, CSC^-1 200
Inverse cotangent arccot, Arccot, ARCCOT, cot^-1, Cot^-1, COT^-1 200
Inverse Hyperbolic sine arsinh, Arsinh, ARSINH, sinh^-1, Sinh^-1, SINH^-1 200
Inverse Hyperbolic cosine arcosh, Arcosh, ARCOSH, cosh^-1, Cosh^-1, COSH^-1 200
Inverse Hyperbolic tangent artanh, Artanh, ARTANH, tanh^-1, Tanh^-1, TANH^-1 200
Inverse Hyperbolic secant arsech, Arsech, ARSECH, sech^-1, Sech^-1, SECH^-1 200
Inverse Hyperbolic cosecant arcsch, Arcsch, ARCSCH, csch^-1, Csch^-1, CSCH^-1 200
Inverse Hyperbolic cotangent arcoth, Arcoth, ARCOTH, coth^-1, Coth^-1, COTH^-1 200
How to evaluate C# math string expression

DotNetStandartMathContext is the .NET Standart 2.1 programming math context supports all constants and functions provided by the System.Math class, and supports equlity, comparision, logical boolean operators.

Example of evaluating C# expression:

"-2 * Math.Log(1/0.5f + Math.Sqrt(1/Math.Pow(0.5d, 2) + 1L))".Evaluate(new DotNetStandartMathContext());

NOTE: More math functions could be added to the math expression evaluator based on user needs.

Contributing

Contributions are welcome! Please fork the repository and submit pull requests for any enhancements or bug fixes. If you enjoy my work and find it valuable, please consider becoming my sponsor on GitHub. Your support will enable me to share more open-source code. Together, we can make a positive impact in the developer community!

License

This project is licensed under the Apache License, Version 2.0 - see the LICENSE file for details.

Contact

If you have any questions or suggestions, feel free to open an issue or contact me directly.

Product Compatible and additional computed target framework versions.
.NET net5.0 was computed.  net5.0-windows was computed.  net6.0 was computed.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 was computed.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
.NET Core netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.1 is compatible. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages

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Version Downloads Last updated
2.2.4 222 10/18/2024
2.2.3 79 10/14/2024
2.2.2 60 10/12/2024
2.2.0 67 10/10/2024
2.1.0 76 10/1/2024
2.0.4 122 9/16/2024
2.0.3 72 9/13/2024
2.0.2 151 9/8/2024
2.0.1 53 9/8/2024
2.0.0 66 9/6/2024
1.1.10 72 9/3/2024
1.1.9 68 8/31/2024
1.1.8 67 8/30/2024
1.1.7 80 8/27/2024

It targets .NET Standard 2.1 and higher version.
Supports different mathematical contexts, such as scientific, programming, and other custom contexts.
Evaluates to double, boolean, or decimal.
Compiles a math expression string into executable code and produces a delegate that represents the math expression.
Provides variable support within math expressions.
Extensible with custom functions and operators.