muParser

muParser

Original author(s)	Ingo Berg
Developer(s)	Ingo Berg, Francesco Montorsi
Initial release	2005; 6 years ago (2005)
Stable release	1.34 / September 4, 2010; 13 months ago (2010-09-04)
Written in	C++
Operating system	Cross-platform
Platform	32-bit, 64-bit
Type	Software library
License	MIT License
Website	muparser.sf.net

muParser is an extensible high-performance math expression parser library written in C++. It works by transforming a mathematical expression into bytecode and precalculating constant parts of the expression. It runs on both 32-bit and 64-bit architectures and has been tested using Visual C++ and GCC. The library is open source and distributed under the MIT License.^[1]

Features

Here is a list of features currently supported by the parser library.^[2]

Overview

• Easy to use (only a few lines of code to evaluate an expression)
• Extremely fast
• User-defined operators (binary, postfix and infix)
• User-defined functions
• User-defined constants
• User-defined variables
• Custom value recognition callbacks
• Default implementation
  • 26 predefined functions
  • 15 predefined operators
  • Supports numerical differentiation with respect to a given variable
  • Assignment operator is supported
• Portability
  • Project / makefiles for MSVC, mingw, autoconf, bcc
  • ISO 14882 compliant code
  • DLL version usable from every language able to use function exported in C-style
• Unit support (postfix operators as unit multipliers)
• Localization (of argument separator, decimal separator, thousands separator)

Built-in Functions

Name	Argument Count	Explanation
sin	1	sine function
cos	1	cosine function
tan	1	tangens function
asin	1	arcus sine function
acos	1	arcus cosine function
atan	1	arcus tangens function
sinh	1	hyperbolic sine function
cosh	1	hyperbolic cosine
tanh	1	hyperbolic tangens function
asinh	1	hyperbolic arcus sine function
acosh	1	hyperbolic arcus tangens function
atanh	1	hyperbolic arcur tangens function
log2	1	logarithm to the base 2
log10	1	logarithm to the base 10
log	1	logarithm to the base 10
ln	1	logarithm to base e (2.71828...)
exp	1	e raised to the power of x
sqrt	1	square root of a value
sign	1	sign function -1 if x<0; 1 if x>0
rint	1	round to nearest integer
abs	1	absolute value
if	3	if ... then ... else ...
min	var.	min of all arguments
max	var.	max of all arguments
sum	var.	sum of all arguments
avg	var.	mean value of all arguments

Built-in operators

Operator	Meaning	Priority
=	assignment*	-1
and	logical and	1
or	logical or	1
xor	logical xor	1
<=	less or equal	2
>=	greater or equal	2
!=	not equal	2
==	equal	2
>	greater than	2
<	less than	2
+	addition	3
-	subtraction	3
*	multiplication	4
/	division	4
^	raise x to the power of y	5

*The assignment operator is special since it changes one of its arguments and can only be applied to variables.

Example Code

#include <iostream>
#include "muParser.h"

// Function callback
double MyFunction(double a_fVal) 
{ 
  return a_fVal*a_fVal; 
}

// main program
int main(int argc, char* argv[])
{
  using namespace mu;

  try
  {
    double fVal = 1;
    Parser p;
    p.DefineVar("a", &fVal); 
    p.DefineFun("MyFunc", MyFunction); 
    p.SetExpr("MyFunc(a)*_pi+min(10,a)");
    std::cout << p.Eval() << std::endl;
  }
  catch (Parser::exception_type &e)
  {
    std::cout << e.GetMsg() << std::endl;
  }
  return 0;
}

References

1. ^ muParser Home Page on SourceForge - http://muparser.sourceforge.net/index.html
2. ^ muParser Features - http://muparser.sourceforge.net/mup_features.html