openswmm::mathexpr Namespace Reference

Classes
struct	Expression
struct	Token

Enumerations
enum class	TokenType : int {   NUMBER = 0 ,   VARIABLE = 1 ,   ADD = 2 ,   SUB = 3 ,   MUL = 4 ,   DIV = 5 ,   POW = 6 ,   NEG = 7 ,   LPAREN = 8 ,   RPAREN = 9 ,   FUNC_ABS = 10 ,   FUNC_SGN = 11 ,   FUNC_SQRT = 12 ,   FUNC_LOG = 13 ,   FUNC_EXP = 14 ,   FUNC_SIN = 15 ,   FUNC_COS = 16 ,   FUNC_TAN = 17 ,   FUNC_ASIN = 18 ,   FUNC_ACOS = 19 ,   FUNC_ATAN = 20 ,   FUNC_STEP = 21 ,   FUNC_MIN = 22 ,   FUNC_MAX = 23 ,   COMMA = 24 ,   FUNC_COT = 25 ,   FUNC_SINH = 26 ,   FUNC_COSH = 27 ,   FUNC_TANH = 28 ,   FUNC_COTH = 29 ,   FUNC_LOG10 = 30 ,   FUNC_ACOT = 31 }

Functions
int	parse (const std::string &expr_str, Expression &result)
	Parse an infix expression string into a postfix Expression.
double	evaluate (const Expression &expr, const std::function< double(const std::string &)> &var_lookup)
	Evaluate a compiled expression with named variable lookup.
double	evaluate (const Expression &expr, const double *vars, int n_vars)
	Evaluate with a flat variable array (by index).
int	bind_variables (Expression &expr, const char *const *name_table, int n_vars)
	Bind variable names in a compiled expression to integer indices.
int	compute_max_stack_depth (const Expression &expr)
	Compute the maximum stack depth needed to evaluate an expression.
double	evaluate_fast (const Expression &expr, const double *vars) noexcept
	Fast evaluate using pre-bound variable indices and stack-free evaluation.

Enumeration Type Documentation

TokenType

enum class openswmm::mathexpr::TokenType : int

strong

Enumerator
NUMBER
VARIABLE
ADD
SUB
MUL
DIV
POW
NEG
LPAREN
RPAREN
FUNC_ABS
FUNC_SGN
FUNC_SQRT
FUNC_LOG
FUNC_EXP
FUNC_SIN
FUNC_COS
FUNC_TAN
FUNC_ASIN
FUNC_ACOS
FUNC_ATAN
FUNC_STEP
FUNC_MIN
FUNC_MAX
COMMA
FUNC_COT	cot(x) = 1/tan(x)
FUNC_SINH	sinh(x)
FUNC_COSH	cosh(x)
FUNC_TANH	tanh(x)
FUNC_COTH	coth(x) = 1/tanh(x)
FUNC_LOG10	log10(x)
FUNC_ACOT	acot(x) = atan(1/x)

Function Documentation

bind_variables()

int openswmm::mathexpr::bind_variables	(	Expression &	expr,
		const char *const *	name_table,
		int	n_vars
	)

Bind variable names in a compiled expression to integer indices.

Resolves each VARIABLE token's var_name to a var_idx using the provided name→index table. After binding, evaluate_fast() can look up variables by index instead of by string comparison.

Parameters

expr	Expression to bind (modified in place).
name_table	Array of variable names, indexed 0..n_vars-1.
n_vars	Number of entries in name_table.

Returns

Number of variables successfully bound.

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compute_max_stack_depth()

int openswmm::mathexpr::compute_max_stack_depth

(

const Expression &

expr

)

Compute the maximum stack depth needed to evaluate an expression.

Parameters

expr	Compiled expression.

Returns

Max stack depth (0 if expression is empty).

evaluate() [1/2]

double openswmm::mathexpr::evaluate	(	const Expression &	expr,
		const double *	vars,
		int	n_vars
	)

Evaluate with a flat variable array (by index).

Parameters

expr	Compiled expression.
vars	Variable values indexed by var_idx.
n_vars	Size of vars array.

Returns

Expression result.

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evaluate() [2/2]

double openswmm::mathexpr::evaluate	(	const Expression &	expr,
		const std::function< double(const std::string &)> &	var_lookup
	)

Evaluate a compiled expression with named variable lookup.

Parameters

expr	Compiled expression.
var_lookup	Function that maps variable name → value.

Returns

Expression result.

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evaluate_fast()

double openswmm::mathexpr::evaluate_fast ( const Expression &  expr, const double *  vars  )

noexcept

Fast evaluate using pre-bound variable indices and stack-free evaluation.

Uses a fixed-size stack array on the C stack (no heap allocation) and reads variables via vars[tok.var_idx] (no string comparison). Variables must be pre-bound via bind_variables().

Parameters

expr	Compiled expression with bound variable indices.
vars	Variable values array. vars[tok.var_idx] is read for each variable.

Returns

Expression result, or 0.0 if expression is invalid.

parse()

int openswmm::mathexpr::parse	(	const std::string &	expr_str,
		Expression &	result
	)

Parse an infix expression string into a postfix Expression.

Parameters

expr_str	Infix expression (e.g., "x * exp(-k * t)").
result	[out] Compiled postfix expression.

Returns

0 on success, -1 on parse error.

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