Medical Imaging Interaction Toolkit
2022.04.9901b95b17
Medical Imaging Interaction Toolkit

This class offers the functionality to evaluate simple mathematical formula strings (e.g. "3.5 + 4 * x * sin(x)  1 / 2"
).
More...
#include <mitkFormulaParser.h>
Public Types  
using  ValueType = double 
using  VariableMapType = std::map< std::string, ValueType > 
Public Member Functions  
FormulaParser (const VariableMapType *variables)  
Construct the FormulaParser and initialized the variables with variables. More...  
ValueType  parse (const std::string &input) 
Evaluates the input string and returns the resulting value. More...  
ValueType  lookupVariable (const std::string var) 
Looks up the associated value of the given string var in the variables map. More...  
This class offers the functionality to evaluate simple mathematical formula strings (e.g. "3.5 + 4 * x * sin(x)  1 / 2"
).
Internally it utilizes the boost::spirit
framework with the Grammar structure to parse the input string into a valid result number. Function strings (e.g. "sin"
, "tan"
or "abs"
) are translated to actual function calls and variables (e.g. "x"
, "myVariable"
, "amount_") are replaced by their currently assigned value via a lookup table.
The parser is able to recognize:
a + b
, 4  3
, 2 * x
, 9 / 3
) +5
, 5
) 2 ^ 4
) 3 * (4 + 2)
) x
, myVar
, test2_var_
) abs
, exp
, sin
, cos
, tan
, sind
(sine in degrees), cosd
(cosine in degrees), tand
(tangent in degrees)In order to use the FormulaParser you just have to initialize it with a map of variables (i.e. a lookup table where "x"
is assigned to 5
for example and "y"
is assigned to 13
and so on) and then call the FormulaParser::parse function with the string that should be evaluated. Be sure to update the lookup table everytime a variable's value changes since that is not done automatically.
Definition at line 64 of file mitkFormulaParser.h.
using mitk::FormulaParser::ValueType = double 
Definition at line 67 of file mitkFormulaParser.h.
using mitk::FormulaParser::VariableMapType = std::map<std::string, ValueType> 
Definition at line 68 of file mitkFormulaParser.h.
mitk::FormulaParser::FormulaParser  (  const VariableMapType *  variables  ) 
Construct the FormulaParser and initialized the variables with variables.
[in]  variables  A map of variables with values that will be assigned to the corresponding member variable. The map is delivered as a pointer so you can still change it from outside this class. 
ValueType mitk::FormulaParser::lookupVariable  (  const std::string  var  ) 
Looks up the associated value of the given string var in the variables map.
[in]  var  The name of the variable whose value is to be returned. 
FormulaParserException  If the variable map is empty or the given variable name cannot be found. 
ValueType mitk::FormulaParser::parse  (  const std::string &  input  ) 
Evaluates the input string and returns the resulting value.
[in]  input  The string to be evaluated. 
FormulaParserException  If
