Engineering tools

Expression Parser

A .NET library for calculations that need to change without recompiling the application. Evaluate formulas supplied as text, using variables, built-in functions and your own functions.

Includes 440+ functions, 80+ units and 47 physical constants for test systems, simulations and engineering software.

Download See examples
"sin(x) * exp(-t/tau) + offset" Expression Parser 0.7854231 Variables x, t, tau, offset Functions sin, exp, sqrt... 440+ Functions 80+ Units 47 Constants <1ms Evaluation
Why Expression Parser

Define and modify calculations at runtime

When a formula is part of the source code, changing it requires a new build. Expression Parser evaluates formulas supplied at runtime, so your application can accept new calculations without recompilation. You control how formulas are loaded, validated and made available to users.

Test systems

Keep measurement calculations separate from test execution code. Supply the formulas needed by each test sequence at runtime.

Machine control

Evaluate formulas for signal conditioning and control calculations. Validate changes and timing requirements within your control application.

Simulations

Compare mathematical models by changing formulas and input variables without rebuilding the simulation application.

Coverage

Functions, units and constants

The library covers general mathematics and calculations used in physics and electronics.

120+

Mathematical functions

Trigonometry, algebra, calculus, statistics, probability, Bessel functions, gamma functions, and more.

50+

Physics functions

Classical mechanics, thermodynamics, electromagnetism, quantum mechanics, optics.

35+

Electronics functions

Circuit analysis, power calculations, filter design, impedance, digital logic.

45+

Logic and Boolean operations

Boolean algebra, bitwise operations, set theory, fuzzy logic, comparisons.

80+

Unit conversions

Convert units of length, mass, temperature, energy, pressure and frequency.

47

Physical constants

Speed of light, Planck constant, gravitational constant, Avogadro number, and more.

Code examples

Evaluate expressions from C#

Basic usage
using ULTRAMEGA.ExpressionParser;

var evaluator = new ExpressionEvaluator();

// Simple calculations
double result1 = evaluator.Evaluate("2 + 3 * 4");       // 14
double result2 = evaluator.Evaluate("sin(pi/4)");       // 0.7071
double result3 = evaluator.Evaluate("sqrt(25)");        // 5

// Using variables
evaluator.SetVariable("x", 5);
evaluator.SetVariable("y", 3);
double result4 = evaluator.Evaluate("x^2 + y^2");       // 34
Engineering calculation
// Beam deflection: δ = FL³/(48EI)
evaluator.SetVariable("F", 10000);      // Force (N)
evaluator.SetVariable("L", 6);          // Length (m)
evaluator.SetVariable("E", 200e9);      // Young's modulus (Pa)
evaluator.SetVariable("I", 8.33e-6);    // Second moment (m⁴)

string formula = "F * L^3 / (48 * E * I)";
double deflection = evaluator.Evaluate(formula);

// Change formula at runtime - no recompile needed
formula = "F * L^3 / (3 * E * I)";  // Cantilever beam
double newDeflection = evaluator.Evaluate(formula);
Physics with constants
// Orbital period using built-in constants
evaluator.SetVariable("M", 5.972e24);   // Earth mass (kg)
evaluator.SetVariable("r", 7000e3);     // Orbital radius (m)

// G (gravitational constant) is built-in
string period = "2 * pi * sqrt(r^3 / (G * M))";
double T = evaluator.Evaluate(period);

// Orbital velocity
double v = evaluator.Evaluate("sqrt(G * M / r)");
Technical specifications

Performance and compatibility

Performance

  • Evaluation: < 1ms
  • Memory: < 5MB
  • Thread-safe: Yes

Compatibility

  • .NET Framework 4.7.2+
  • .NET Core 3.1+
  • .NET 5, 6, 7, 8

Features

  • Detailed error messages
  • Expression validation
  • Custom function support

Performance figures are from internal benchmarks, not guaranteed limits. Results depend on the expression, hardware and workload. Contact us for the benchmark conditions.

Get Expression Parser

Download the .NET library from our downloads page. Contact us to discuss licensing, supported .NET versions or integration with your application.

Go to downloads Contact us