openswmm::snow::DegreeDaySnow Class Reference

#include <DegreeDaySnow.hpp>

Inheritance diagram for openswmm::snow::DegreeDaySnow:

Collaboration diagram for openswmm::snow::DegreeDaySnow:

Public Member Functions
void	init (int n_subcatch)
	Reset native three-subarea storage through SnowSoA::resize().
void	initializeElements (int n) override
	Allocate native storage rounded up to whole three-element packs.
void	step (int e, const surface::SnowInputs &input, surface::SnowOutputs &output) override
	Accumulate and melt one SI point element without batch plowing.
int	stateSize () const override
	Read the fixed native per-element payload size.
void	pack (int e, double *output) const override
	Copy twelve native element history values without validating the buffer.
void	unpack (int e, const double *input) override
	Assign twelve native element history fields from a matching payload.
void	execute (SimulationContext &ctx, double dt, double temp, double wind, const double *rainfall, const double *snowfall, double gamma=0.0, double ea=0.0) override
	Melt every enabled native-owned batch pack after snowfall/plowing preparation.
void	execute (SimulationContext &ctx, double dt, double temp, double wind, double rainfall, double snowfall=0.0, double gamma=0.0, double ea=0.0)
	Broadcast native precipitation rates then call the array melt overload.
void	setMeltCoeffs (int day_of_year)
	Update every native subarea's seasonal degree-day coefficient.
void	plowSnow (SimulationContext &ctx, double dt, const double *snowfall) override
	Add native snowfall once, age packs, then redistribute plowable solid snow.
void	plowSnow (SimulationContext &ctx, double dt, double snowfall)
	Broadcast uniform snowfall then use native accumulation/plowing.
SnowSoA &	state ()
	Borrow mutable native geometry, controls, ownership and pack history.
const SnowSoA &	state () const
	Borrow immutable current native snow state and liquid-flux outputs.
Public Member Functions inherited from openswmm::surface::SnowModel
virtual	~SnowModel ()=default
	Destroy derived owned snow state through the base interface. Caller ends all active callbacks/borrows before destruction; no implicit commit.

Member Function Documentation

execute() [1/2]

void openswmm::snow::DegreeDaySnow::execute ( SimulationContext & ctx, double dt, double temp, double wind, const double * rainfall, const double * snowfall, double gamma = 0.0, double ea = 0.0 )

overridevirtual

Melt every enabled native-owned batch pack after snowfall/plowing preparation.

Parameters

ctx	Unused by this degree-day melt overload; geometry is already in soa_.
dt	Finite positive seconds, unchecked and used as divisor.
temp	Held air Fahrenheit.
wind	Held nonnegative mph for rain-on-snow.
rainfall	Readable n_subcatch finite nonnegative ft/s values.
snowfall	Readable n_subcatch finite nonnegative ft/s values, already added to wsnow by plowSnow; used for depletion/cold-content transitions, not added again.
gamma	Native psychrometric coefficient F^-1, default zero.
ea	Native vapour pressure in Hg, default zero. Processes three subareas in order, skips disabled/external source rows, computes liquid melt/coverage and optional out_age. Must pair exactly once with plowSnow and current setMeltCoeffs; does not advance context date or perform external UEB. No-op when n_subcatch==0. Invalid inputs can propagate without status/rollback.

Implements openswmm::surface::SnowModel.

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execute() [2/2]

void openswmm::snow::DegreeDaySnow::execute	(	SimulationContext &	ctx,
		double	dt,
		double	temp,
		double	wind,
		double	rainfall,
		double	snowfall = 0.0,
		double	gamma = 0.0,
		double	ea = 0.0 )

Broadcast native precipitation rates then call the array melt overload.

Parameters

ctx	Forwarded compatible context; unused by the degree-day melt kernel.
dt	Finite positive interval seconds.
temp	Held Fahrenheit.
wind	Held mph.
rainfall	Uniform finite nonnegative rain ft/s.
snowfall	Uniform snow ft/s, already accumulated by prior plowSnow.
gamma	Native psychrometric F^-1 coefficient.
ea	Native vapour pressure in Hg. Allocates temporary n_subcatch arrays, no-op for zero sources. Same ownership/ sequence/output contract as array execute; allocation exceptions propagate.

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init()

void openswmm::snow::DegreeDaySnow::init

(

int

n_subcatch

)

Reset native three-subarea storage through SnowSoA::resize().

Parameters

n_subcatch

Nonnegative model source count with safe integer products/storage. Does not populate snowpack geometry/parameters or reset retained global controls/ removed totals. Caller configures compatible state before accumulation/melt.

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initializeElements()

void openswmm::snow::DegreeDaySnow::initializeElements ( int n )

inlineoverridevirtual

Allocate native storage rounded up to whole three-element packs.

Parameters

n

Nonnegative requested point count with n+2 representable as int. Calls init(ceil(n/3)), so actual step capacity is 3*ceil(n/3); extra slots are allocated/defaulted too. Does not load physical parameters or distinguish mesh from native sources; caller supplies per-element configuration and ownership.

Implements openswmm::surface::SnowModel.

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pack()

void openswmm::snow::DegreeDaySnow::pack ( int e, double * output ) const

overridevirtual

Copy twelve native element history values without validating the buffer.

Parameters

	e	Valid allocated flat index, unchecked.
[out]	output	Writable twelve doubles: wsnow/fw/coldc(ft), ati(F), awe, imelt(ft/s), si(ft), sba/sbws/asc (depletion fractions/indices), age/out_age(seconds). No metadata/version, unit conversion, global state or complete restart identity. Serialize reads with mutation; pointer is borrowed only during the call.

Implements openswmm::surface::SnowModel.

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plowSnow() [1/2]

void openswmm::snow::DegreeDaySnow::plowSnow ( SimulationContext & ctx, double dt, const double * snowfall )

overridevirtual

Add native snowfall once, age packs, then redistribute plowable solid snow.

Parameters

[in,out]	ctx	Compatible source geometry/project units, total LID areas and cross-source plow destinations; context is read for physical non-LID footprints.
	dt	Finite positive seconds; no general validation (instant plow melt alone guards dt>0). Caller follows once with execute() for the same interval.
	snowfall	Readable n_subcatch finite nonnegative snow ft/s values. Skips disabled/external donor sources. First pass ages existing complete-mix water and adds new snow at precip_age, then a separate pass plows to removal, native impervious/pervious, instant melt or another pervious source. Zero threshold plows every step. Fractions/areas must be qualified; only their total donor subtraction is capped at one. Conservative mode or external receivers include donor/receiver physical-area ratio; ordinary legacy transfer preserves its fraction-only arithmetic. Can transfer cold energy to an external UEB receiver and records removed ft3. Mutates owned histories immediately; no conservation diagnostic/rollback or clock advance, and external receivers must be settled by their own qualified driver.

Implements openswmm::surface::SnowModel.

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plowSnow() [2/2]

void openswmm::snow::DegreeDaySnow::plowSnow	(	SimulationContext &	ctx,
		double	dt,
		double	snowfall )

Broadcast uniform snowfall then use native accumulation/plowing.

Parameters

[in,out]	ctx	Compatible geometry/units forwarded to array plowSnow.
	dt	Finite positive seconds.
	snowfall	Uniform finite nonnegative ft/s, added exactly once per enabled native pack before melt execution. No-op with zero sources; temporary allocation can throw. Same plowing/age/ownership and immediate-mutation contract as array overload.

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setMeltCoeffs()

void openswmm::snow::DegreeDaySnow::setMeltCoeffs

(

int

day_of_year

)

Update every native subarea's seasonal degree-day coefficient.

Parameters

day_of_year

Valid ordinal [1,366], unchecked. Stores sin(0.0172615*(day-81)) season and interpolates current dhm from dhmin/dhmax. This legacy phase/period is preserved, not normalized to 365 days. Does not advance water, reset age/fluxes, load parameters or skip externally owned/masked rows.

state() [1/2]

SnowSoA & openswmm::snow::DegreeDaySnow::state ( )

inline

Borrow mutable native geometry, controls, ownership and pack history.

Returns

Owned SoA; resize/init/move/destruction can invalidate elements. Caller keeps all arrays aligned and physically valid and serializes edits with every snow call. No automatic model qualification, external UEB synchronization or trial rollback.

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state() [2/2]

const SnowSoA & openswmm::snow::DegreeDaySnow::state ( ) const

inline

Borrow immutable current native snow state and liquid-flux outputs.

Returns

Owned SoA, flat source*3+subarea layout. Current imelt is ft/s; out_age seconds meaningful only for positive emitted liquid. Init/resize/replacement can invalidate elements and stepping changes contents; copy stable snapshots as needed.

stateSize()

int openswmm::snow::DegreeDaySnow::stateSize ( ) const

inlineoverridevirtual

Read the fixed native per-element payload size.

Returns

Twelve doubles; pack/unpack omit geometry/global parameters, removed total, source masks, pending UEB transfer energy and external-solver runtime ownership.

Implements openswmm::surface::SnowModel.

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step()

void openswmm::snow::DegreeDaySnow::step ( int e, const surface::SnowInputs & input, surface::SnowOutputs & output )

overridevirtual

Accumulate and melt one SI point element without batch plowing.

Parameters

	e	Flat allocated element index (source*3+subarea); invalid returns zeroed output.
	input	Finite positive dt_s; interval rain/snow depths metres, temperature C, wind m/s and native gamma/ea. Other weather/energy fields are ignored by degree day.
[out]	output	Reset first, even for invalid index/nonpositive dt. Replaces melt_m with total liquid pack drainage, throughfall_m with uncovered rain, swe_m with snow+free water and cover_frac. Thermal/albedo/sublimation fields stay zero. Adds snowfall once, ages/mixes the optional complete snow/free-water age pool and uses current seasonal melt coefficients/depletion history. Does not honor native enabled/external source masks or perform inter-element plowing: caller exclusively owns this element and sets coefficients first. No finite-input checks, status or rollback; dt NaN is not caught by the nonpositive guard.

Implements openswmm::surface::SnowModel.

unpack()

void openswmm::snow::DegreeDaySnow::unpack ( int e, const double * input )

overridevirtual

Assign twelve native element history fields from a matching payload.

Parameters

e	Valid allocated flat index, unchecked.
input	Readable twelve doubles in pack() order/native units. No finite, nonnegative, coverage or model/shape validation; caller qualifies payload before publishing a restart. Does not restore geometry/globals/masks or resize storage.

Implements openswmm::surface::SnowModel.

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The documentation for this class was generated from the following files:

• /home/runner/work/openswmm.engine/openswmm.engine/src/engine/hydrology/surface/DegreeDaySnow.hpp
• /home/runner/work/openswmm.engine/openswmm.engine/src/engine/hydrology/surface/DegreeDaySnow.cpp