Nodal Demand Functions

These functions are used for managing nodal demands. More...

Functions
int	EN_getdemandmodel (EN_Project ph, int *type, double *pmin, double *preq, double *pexp)
	Retrieves the type of demand model in use and its parameters. More...
int	EN_setdemandmodel (EN_Project ph, int type, double pmin, double preq, double pexp)
	Sets the type of demand model to use and its parameters. More...
int	EN_adddemand (EN_Project ph, int nodeIndex, double baseDemand, char *demandPattern, char *demandName)
	appends a new demand to a junction node demands list. More...
int	EN_deletedemand (EN_Project ph, int nodeIndex, int demandIndex)
	deletes a demand from a junction node. More...
int	EN_getdemandindex (EN_Project ph, int nodeIndex, char *demandName, int *demandIndex)
	Retrieves the index of a node's named demand category. More...
int	EN_getnumdemands (EN_Project ph, int nodeIndex, int *numDemands)
	Retrieves the number of demand categories for a junction node. More...
int	EN_getbasedemand (EN_Project ph, int nodeIndex, int demandIndex, double *baseDemand)
	Gets the base demand for one of a node's demand categories. More...
int	EN_setbasedemand (EN_Project ph, int nodeIndex, int demandIndex, double baseDemand)
	Sets the base demand for one of a node's demand categories. More...
int	EN_getdemandpattern (EN_Project ph, int nodeIndex, int demandIndex, int *patIndex)
	Retrieves the index of a time pattern assigned to one of a node's demand categories. More...
int	EN_setdemandpattern (EN_Project ph, int nodeIndex, int demandIndex, int patIndex)
	Sets the index of a time pattern used for one of a node's demand categories. More...
int	EN_getdemandname (EN_Project ph, int nodeIndex, int demandIndex, char *out_demandName)
	Retrieves the name of a node's demand category. More...
int	EN_setdemandname (EN_Project ph, int nodeIndex, int demandIdx, char *demandName)
	Assigns a name to a node's demand category. More...

Overview

These functions are used for managing nodal demands.

Function Documentation

EN_adddemand()

int EN_adddemand	(	EN_Project	ph,
		int	nodeIndex,
		double	baseDemand,
		char *	demandPattern,
		char *	demandName
	)

appends a new demand to a junction node demands list.

Parameters

ph	an EPANET project handle.
nodeIndex	the index of a node (starting from 1).
baseDemand	the demand's base value.
demandPattern	the name of a time pattern used by the demand
demandName	the name of the demand's category

Returns

an error code.

A NULL or blank string can be used for demandPattern and for demandName to indicate that no time pattern or category name is associated with the demand.

EN_deletedemand()

int EN_deletedemand	(	EN_Project	ph,
		int	nodeIndex,
		int	demandIndex
	)

deletes a demand from a junction node.

Parameters

ph	an EPANET project handle.
nodeIndex	the index of a node (starting from 1).
demandIndex	the position of the demand in the node's demands list (starting from 1).

Returns

an error code.

EN_getbasedemand()

int EN_getbasedemand	(	EN_Project	ph,
		int	nodeIndex,
		int	demandIndex,
		double *	baseDemand
	)

Gets the base demand for one of a node's demand categories.

Parameters

	ph	an EPANET project handle.
	nodeIndex	a node's index (starting from 1).
	demandIndex	the index of a demand category for the node (starting from 1).
[out]	baseDemand	the category's base demand.

Returns

an error code.

EN_getdemandindex()

int EN_getdemandindex	(	EN_Project	ph,
		int	nodeIndex,
		char *	demandName,
		int *	demandIndex
	)

Retrieves the index of a node's named demand category.

Parameters

	ph	an EPANET project handle.
	nodeIndex	the index of a node (starting from 1)
	demandName	the name of a demand category for the node
[out]	demandIndex	the index of the demand being sought

Returns

an error code

EN_getdemandmodel()

int EN_getdemandmodel	(	EN_Project	ph,
		int *	type,
		double *	pmin,
		double *	preq,
		double *	pexp
	)

Retrieves the type of demand model in use and its parameters.

Parameters

	ph	an EPANET project handle.
[out]	type	Type of demand model (see EN_DemandModel).
[out]	pmin	Pressure below which there is no demand.
[out]	preq	Pressure required to deliver full demand.
[out]	pexp	Pressure exponent in demand function.

Returns

an error code.

Parameters pmin, preq, and pexp are only used when the demand model is EN_PDA.

EN_getdemandname()

int EN_getdemandname	(	EN_Project	ph,
		int	nodeIndex,
		int	demandIndex,
		char *	out_demandName
	)

Retrieves the name of a node's demand category.

Parameters

	ph	an EPANET project handle.
	nodeIndex	a node's index (starting from 1).
	demandIndex	the index of one of the node's demand categories (starting from 1).
[out]	out_demandName	The name of the selected category.

Returns

an error code.

demandName must be sized to contain at least EN_MAXID characters.

EN_getdemandpattern()

int EN_getdemandpattern	(	EN_Project	ph,
		int	nodeIndex,
		int	demandIndex,
		int *	patIndex
	)

Retrieves the index of a time pattern assigned to one of a node's demand categories.

Parameters

	ph	an EPANET project handle.
	nodeIndex	the node's index (starting from 1).
	demandIndex	the index of a demand category for the node (starting from 1).
[out]	patIndex	the index of the category's time pattern.

Returns

an error code.

A returned pattern index of 0 indicates that no time pattern has been assigned to the demand category.

EN_getnumdemands()

int EN_getnumdemands	(	EN_Project	ph,
		int	nodeIndex,
		int *	numDemands
	)

Retrieves the number of demand categories for a junction node.

Parameters

	ph	an EPANET project handle.
	nodeIndex	the index of a node (starting from 1).
[out]	numDemands	the number of demand categories assigned to the node.

Returns

an error code.

EN_setbasedemand()

int EN_setbasedemand	(	EN_Project	ph,
		int	nodeIndex,
		int	demandIndex,
		double	baseDemand
	)

Sets the base demand for one of a node's demand categories.

Parameters

ph	an EPANET project handle.
nodeIndex	a node's index (starting from 1).
demandIndex	the index of a demand category for the node (starting from 1).
baseDemand	the new base demand for the category.

Returns

an error code.

EN_setdemandmodel()

int EN_setdemandmodel	(	EN_Project	ph,
		int	type,
		double	pmin,
		double	preq,
		double	pexp
	)

Sets the type of demand model to use and its parameters.

Parameters

ph	an EPANET project handle.
type	Type of demand model (see EN_DemandModel).
pmin	Pressure below which there is no demand.
preq	Pressure required to deliver full demand.
pexp	Pressure exponent in demand function.

Returns

an error code.

Set type to EN_DDA for a traditional demand driven analysis (in which case the remaining three parameter values are ignored) or to EN_PDA for a pressure driven analysis. In the latter case a node's demand is computed as:

Dfull * [ (P - pmin) / (preq - pmin) ] ^ pexp

where Dfull is the full demand and P is the current pressure.

Setting preq equal to pmin will result in a solution with the smallest amount of demand reductions needed to insure that no node delivers positive demand at a pressure below pmin.

EN_setdemandname()

int EN_setdemandname	(	EN_Project	ph,
		int	nodeIndex,
		int	demandIdx,
		char *	demandName
	)

Assigns a name to a node's demand category.

Parameters

ph	an EPANET project handle.
nodeIndex	a node's index (starting from 1).
demandIdx	the index of one of the node's demand categories (starting from 1).
demandName	the new name assigned to the category.

Returns

Error code.

The category name must contain no more than EN_MAXID characters.

EN_setdemandpattern()

int EN_setdemandpattern	(	EN_Project	ph,
		int	nodeIndex,
		int	demandIndex,
		int	patIndex
	)

Sets the index of a time pattern used for one of a node's demand categories.

Parameters

ph	an EPANET project handle.
nodeIndex	a node's index (starting from 1).
demandIndex	the index of one of the node's demand categories (starting from 1).
patIndex	the index of the time pattern assigned to the category.

Returns

an error code.

Specifying a pattern index of 0 indicates that no time pattern is assigned to the demand category.