openswmm::twoD::exchange Namespace Reference

Classes
struct	Coefficients
	Discharge coefficients and the φ regularisation head. More...
struct	Geometry
	A coupling point's structure, SI. More...
struct	Result

Functions
OPENSWMM_EXCHANGE_HD double	phi (double x, double eps)
	C¹-regularised √x: √x for x ≥ ε, (3/(2√ε))x − x²/(2ε^{3/2}) below.
OPENSWMM_EXCHANGE_HD double	dphi (double x, double eps)
	dφ/dx (finite at 0).
OPENSWMM_EXCHANGE_HD double	smoothstep (double t)
	Hermite smoothstep of t clamped to [0, 1].
OPENSWMM_EXCHANGE_HD double	softmin (double a, double b, double &wa, double &wb)
	p-norm minimum, p = 16: (a^−16 + b^−16)^(−1/16) for a, b > 0, else 0. Evaluated as min / (1 + r^16)^(1/16), r = min/max ∈ (0, 1], with four square roots — no overflow, no pow. Weights ∂Q/∂a, ∂Q/∂b go to wa, wb.
OPENSWMM_EXCHANGE_HD Result	exchange (const Geometry &geo, const Coefficients &c, double h2, double h1)
	Evaluate the bidirectional regularized weir/orifice exchange and damping.

Variables
constexpr double	kGravity = 9.80665
	m/s²
constexpr double	kSigmaBand = 0.1
	submergence blend width

Function Documentation

dphi()

OPENSWMM_EXCHANGE_HD double openswmm::twoD::exchange::dphi	(	double	x,
		double	eps )

dφ/dx (finite at 0).

Parameters

[in]	x	Finite head difference in m; nonpositive values use the positive-side regularization derivative at zero.
[in]	eps	Finite strictly positive regularization head, m.

Returns

Positive-side derivative in 1/sqrt(m); for x <= 0 this is not the derivative of the clamped negative branch.

Note

Pure host/device scalar evaluation; invalid eps is not checked.

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exchange()

OPENSWMM_EXCHANGE_HD Result openswmm::twoD::exchange::exchange	(	const Geometry &	geo,
		const Coefficients &	c,
		double	h2,
		double	h1 )

Evaluate the bidirectional regularized weir/orifice exchange and damping.

Parameters

[in]	geo	Borrowed validated geometry: crest m, weir length m, orifice area m2.
[in]	c	Borrowed nonnegative discharge coefficients and strictly positive h_eps in m.
[in]	h2	Finite surface water head, m in the crest datum.
[in]	h1	Finite network-node water head, m in the same datum.

Returns

Value-owned Result: q in m3/s, positive surface-to-network and negative network-to-surface; g in m2/s is nonnegative damping, with blend-weight derivatives deliberately omitted. Equal or below-crest inactive heads return zero.

Note

Inputs are not validated. Pure host/device calculation; no availability limiter, ledger mutation, or retained references.

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phi()

OPENSWMM_EXCHANGE_HD double openswmm::twoD::exchange::phi	(	double	x,
		double	eps )

C¹-regularised √x: √x for x ≥ ε, (3/(2√ε))x − x²/(2ε^{3/2}) below.

Parameters

[in]	x	Finite head difference in m; nonpositive values return zero.
[in]	eps	Finite strictly positive regularization head, m.

Returns

Regularized square root in sqrt(m).

Note

Pure host/device scalar evaluation; invalid eps is not checked.

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smoothstep()

OPENSWMM_EXCHANGE_HD double openswmm::twoD::exchange::smoothstep

(

double

t

)

Hermite smoothstep of t clamped to [0, 1].

Parameters

[in]

t

Finite dimensionless blend coordinate; clamped to [0,1].

Returns

Dimensionless Hermite blend in [0,1], with zero slope at both endpoints.

Note

Pure host/device calculation with no retained state.

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softmin()

OPENSWMM_EXCHANGE_HD double openswmm::twoD::exchange::softmin	(	double	a,
		double	b,
		double &	wa,
		double &	wb )

p-norm minimum, p = 16: (a^−16 + b^−16)^(−1/16) for a, b > 0, else 0. Evaluated as min / (1 + r^16)^(1/16), r = min/max ∈ (0, 1], with four square roots — no overflow, no pow. Weights ∂Q/∂a, ∂Q/∂b go to wa, wb.

Parameters

[in]	a	Finite nonnegative first candidate flow, m3/s.
[in]	b	Finite nonnegative second candidate flow, m3/s.
[out]	wa	Dimensionless sensitivity to a; set to zero if either candidate is nonpositive.
[out]	wb	Dimensionless sensitivity to b; set to zero if either candidate is nonpositive.

Returns

Smoothed limiting discharge in m3/s, no greater than min(a,b); zero if either candidate is nonpositive.

Precondition

wa and wb refer to separate output scalars. No pointer/state ownership or allocation.

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Variable Documentation

kGravity

double openswmm::twoD::exchange::kGravity = 9.80665

constexpr

m/s²

kSigmaBand

double openswmm::twoD::exchange::kSigmaBand = 0.1

constexpr

submergence blend width