MathExpr.hpp File Reference

Mathematical expression parser and evaluator. More...

#include <string>
#include <vector>
#include <functional>

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Classes
struct	openswmm::mathexpr::Token
struct	openswmm::mathexpr::Expression

Namespaces
namespace	openswmm
namespace	openswmm::mathexpr

Enumerations
enum class	openswmm::mathexpr::TokenType : int {   openswmm::mathexpr::NUMBER = 0 ,   openswmm::mathexpr::VARIABLE = 1 ,   openswmm::mathexpr::ADD = 2 ,   openswmm::mathexpr::SUB = 3 ,   openswmm::mathexpr::MUL = 4 ,   openswmm::mathexpr::DIV = 5 ,   openswmm::mathexpr::POW = 6 ,   openswmm::mathexpr::NEG = 7 ,   openswmm::mathexpr::LPAREN = 8 ,   openswmm::mathexpr::RPAREN = 9 ,   openswmm::mathexpr::FUNC_ABS = 10 ,   openswmm::mathexpr::FUNC_SGN = 11 ,   openswmm::mathexpr::FUNC_SQRT = 12 ,   openswmm::mathexpr::FUNC_LOG = 13 ,   openswmm::mathexpr::FUNC_EXP = 14 ,   openswmm::mathexpr::FUNC_SIN = 15 ,   openswmm::mathexpr::FUNC_COS = 16 ,   openswmm::mathexpr::FUNC_TAN = 17 ,   openswmm::mathexpr::FUNC_ASIN = 18 ,   openswmm::mathexpr::FUNC_ACOS = 19 ,   openswmm::mathexpr::FUNC_ATAN = 20 ,   openswmm::mathexpr::FUNC_STEP = 21 ,   openswmm::mathexpr::FUNC_MIN = 22 ,   openswmm::mathexpr::FUNC_MAX = 23 ,   openswmm::mathexpr::COMMA = 24 }

Functions
int	openswmm::mathexpr::parse (const std::string &expr_str, Expression &result)
	Parse an infix expression string into a postfix Expression.
double	openswmm::mathexpr::evaluate (const Expression &expr, const std::function< double(const std::string &)> &var_lookup)
	Evaluate a compiled expression with named variable lookup.
double	openswmm::mathexpr::evaluate (const Expression &expr, const double *vars, int n_vars)
	Evaluate with a flat variable array (by index).

Detailed Description

Mathematical expression parser and evaluator.

Parses infix expressions (e.g., "C * exp(-0.1 * DT)") into postfix (RPN) token lists using the Shunting-yard algorithm. Evaluation uses a simple stack machine.

Used by:

• Control rules (IF conditions with expressions)
• Treatment functions (pollutant concentration formulas)
• Groundwater custom deep flow expressions

Note

Legacy reference: src/legacy/engine/mathexpr.c

Author

Caleb Buahin caleb.nosp@m..bua.nosp@m.hin@g.nosp@m.mail.nosp@m..com

Copyright

Copyright (c) 2026 HydroCouple. All rights reserved.

License\n MIT License