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Jpye: /* Declarative FOR statement (FOR..CREATE) */

2013-11-17T02:35:46Z

Declarative FOR statement (FOR..CREATE)

← Older revision		Revision as of 02:35, 17 November 2013
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	== Declarative FOR statement (FOR..CREATE) ==		== Declarative FOR statement (FOR..CREATE) ==
	FOR..CREATE statements are used with the ''declarative'' part of a model to declare many similar equations or variables. The statement is 'FOR..CREATE' to reflect the fact that for each iteration of the loop, a new equation or variable is added (permanently) to the model.		FOR..CREATE statements are used with the ''declarative'' part of a model to declare many similar equations or variables. The statement is 'FOR..CREATE' to reflect the fact that for each iteration of the loop, a new equation or variable is added (permanently) to the model. In the example below, equations are added via refinement of a sub-model using [[IS_REFINED_TO]].

	<source lang="a4c">		<source lang="a4c">

Jpye at 02:33, 17 November 2013

2013-11-17T02:33:14Z

← Older revision		Revision as of 02:33, 17 November 2013
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	FOR..CREATE statements are used with the ''declarative'' part of a model to declare many similar equations or variables. The statement is 'FOR..CREATE' to reflect the fact that for each iteration of the loop, a new equation or variable is added (permanently) to the model.		FOR..CREATE statements are used with the ''declarative'' part of a model to declare many similar equations or variables. The statement is 'FOR..CREATE' to reflect the fact that for each iteration of the loop, a new equation or variable is added (permanently) to the model.

	<source lang="a4c">A[1..4] IS_A finite_difference;		<source lang="a4c">
			A[1..4] IS_A finite_difference;
	FOR i IN [1,2,3,4] CREATE		FOR i IN [1,2,3,4] CREATE

	A[i] IS_REFINED_TO central_difference(x[i-1],x[i+1]);		A[i] IS_REFINED_TO central_difference(x[i-1],x[i+1]);
			END FOR;
	END FOR;</source>		</source>

	== Procedural FOR statement (FOR..DO) ==		== Procedural FOR statement (FOR..DO) ==
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	This is used to perform actions on your model, such as [[FIX\|FIXing]] variables, setting values, etc:		This is used to perform actions on your model, such as [[FIX\|FIXing]] variables, setting values, etc:

	<source lang="a4c">FOR i IN [1,2,3,4] DO		<source lang="a4c">
			FOR i IN [1,2,3,4] DO
	x[i]~~ ~~:= 7 + 0.1 * i;		x[i] := 7 + 0.1 * i;
			END FOR;
	END FOR;</source>		</source>

	Note that reverse-order loops are possible, using		Note that reverse-order loops are possible, using

	<source lang="a4c">FOR i IN [n_stages..1] DECREASING DO		<source lang="a4c">
			FOR i IN [n_stages..1] DECREASING DO
	(* statements here *)		(* statements here *)
	END FOR;</source>		END FOR;
			</source>

	== See also ==		== See also ==
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	* Further syntax information and examples in the PDF file linked to from [[Category:Documentation]].		* Further syntax information and examples in the PDF file linked to from [[Category:Documentation]].

			[[Category:Documentation]]

	[[Category:Documentation]]
	[[Category:Syntax]]		[[Category:Syntax]]

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The '''FOR''' statement exists in two forms, declarative and procedural.

== Declarative FOR statement (FOR..CREATE) ==
FOR..CREATE statements are used with the ''declarative'' part of a model to declare many similar equations or variables. The statement is 'FOR..CREATE' to reflect the fact that for each iteration of the loop, a new equation or variable is added (permanently) to the model.

<source lang="a4c">A[1..4] IS_A finite_difference;

FOR i IN [1,2,3,4] CREATE

A[i] IS_REFINED_TO central_difference(x[i-1],x[i+1]);

END FOR;</source>

== Procedural FOR statement (FOR..DO) ==

When FOR statements are used with [[METHOD|METHODs]], they can contain procedural code that is run whenever the METHOD is run.
This is used to perform actions on your model, such as [[FIX|FIXing]] variables, setting values, etc:

<source lang="a4c">FOR i IN [1,2,3,4] DO

x[i] := 7 + 0.1 * i;

END FOR;</source>

Note that reverse-order loops are possible, using

<source lang="a4c">FOR i IN [n_stages..1] DECREASING DO

(* statements here *)
END FOR;</source>

== See also ==

* [[Arrays and sets]] (usually you will be using arrays within your FOR loops)
* [[WHILE]]
* Further syntax information and examples in the PDF file linked to from [[Category:Documentation]].

[[Category:Documentation]]
[[Category:Syntax]]