Arrays and sets - Revision history

Jpye: /* Adding and subtracting sets */

2012-10-02T09:26:51Z

Adding and subtracting sets

← Older revision		Revision as of 09:26, 2 October 2012
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	END mymodel;</source>		END mymodel;</source>

	Note the use of the [[SUM]] statement for looping through elements of a set and adding up the resulting expressions.		Note the use of the [[SUM]] statement for looping through elements of a set and adding up the resulting expressions. Inside the sum is the '<nowiki>\|</nowiki>' or <tt>SUCH_THAT</tt> operator ('\|' is simply shorthand for the longhand version, '<tt>SUCH_THAT</tt>'.).

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

Jpye: /* Adding and subtracting sets */

2011-04-28T01:17:32Z

Adding and subtracting sets

← Older revision		Revision as of 01:17, 28 April 2011
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	(* initialise those same elements to 290 K *)		(* initialise those same elements to 290 K *)
	FOR i IN B DO		FOR i IN B DO
	a[i]~~ ~~:= 290 {K};		a[i] := 290 {K};

	END FOR;		END FOR;
	(* initialise the remaining elements to 320 K *)		(* initialise the remaining elements to 320 K *)
	a[C]~~ ~~:= 320 {K};		a[C] := 320 {K};

	END on_load;		END on_load;

Jpye at 02:05, 1 March 2011

2011-03-01T02:05:54Z

← Older revision		Revision as of 02:05, 1 March 2011
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	See also [[Thin-walled tank/Arrays]].		See also [[Thin-walled tank/Arrays]].


	== [[FOR]] loops ==		== [[FOR]] loops ==
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	See the [[FOR]] for more information.		See the [[FOR]] for more information.


	== Counting elements in sets using <tt>CARD</tt> ==		== Counting elements in sets using <tt>CARD</tt> ==
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	'''Note''': you can't use the <tt>CARD</tt> function in equations; it is only able to be used when assigning values to constants.		'''Note''': you can't use the <tt>CARD</tt> function in equations; it is only able to be used when assigning values to constants.


	== Adding and subtracting sets ==		== Adding and subtracting sets ==

Jpye at 02:05, 1 March 2011

2011-03-01T02:05:39Z

← Older revision		Revision as of 02:05, 1 March 2011
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	Note the use of the [[SUM]] statement for looping through elements of a set and adding up the resulting expressions.		Note the use of the [[SUM]] statement for looping through elements of a set and adding up the resulting expressions.




	~~[[Category:Incomplete]]~~
	[[Category:Documentation]]		[[Category:Documentation]]
	[[Category:Syntax]]		[[Category:Syntax]]

Jpye at 02:05, 1 March 2011

2011-03-01T02:05:21Z

← Older revision		Revision as of 02:05, 1 March 2011
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	~~<div>''This article is~~ incomplete ~~or needs expanding. Please help out by adding your comments.''</div>~~		{{incomplete}}
	This page will be expanded to include use of ~~SETs~~ and arrays in ASCEND. For the moment here are some quick examples:		This page will be expanded to include use of sets and arrays in ASCEND. For the moment here are some quick examples:
	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang="a4c">REQUIRE "atoms.a4l";

	MODEL mymodel;		MODEL mymodel;
Line 57:		Line 57:
	Sets can be useful for slicing up arrays in different ways, for example:		Sets can be useful for slicing up arrays in different ways, for example:

	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang="a4c">REQUIRE "atoms.a4l";
	MODEL mymodel;		MODEL mymodel;
	A, B, C IS_A set OF integer_constant;		A, B, C IS_A set OF integer_constant;

UploadBot: Restored page from Google Cache, uploaded by John Pye

2010-05-13T14:00:24Z

Restored page from Google Cache, uploaded by John Pye

New page

<div>''This article is incomplete or needs expanding. Please help out by adding your comments.''</div>
This page will be expanded to include use of SETs and arrays in ASCEND. For the moment here are some quick examples:
<source lang="a4c">REQUIRE "atoms.a4l";

MODEL mymodel;
(* declare a new set -- but note that its members could be declared in a sub-model if desired *)
myset IS_A set OF symbol_constant;

(* declare the members of the set -- note, this is done in the declarative section because the set is constant-valued *)
myset :== ['A','B','D'];

(* declare an array that contains elements indexed by the members of the myset *)

myarray[myset] IS_A distance;

(* write a relationship between the values of this array *)
myarray['A'] = myarray['B'] + 1;

METHODS
METHOD on_load;
(* fix all members in myarray *)
FIX myarray[myset];

(* free just one member *)
FREE myarray['A'];
END on_load;
END mymodel;</source>

See also [[Thin-walled tank/Arrays]].

== [[FOR]] loops ==

ASCEND provides looping syntax. The syntax used depends on whether you are in the declarative (main) part of your model (FOR..CREATE), or in the procedural part of the model (FOR..DO).

See the [[FOR]] for more information.

== Counting elements in sets using <tt>CARD</tt> ==

In ASCEND, the function '''<tt>CARD[set]</tt>''' can be used to count the number of elements in a set. A typical use is as follows:

<source lang="a4c">A IS_A set OF symbol_constant;

A :== ['A','B','C','D'];
n_A IS_A integer_constant;

n_A :== CARD[A];</source>

Now the value of n_A will be set to 4.

'''Note''': you can't use the <tt>CARD</tt> function in equations; it is only able to be used when assigning values to constants.

== Adding and subtracting sets ==

Sets can be useful for slicing up arrays in different ways, for example:

<source lang="a4c">REQUIRE "atoms.a4l";
MODEL mymodel;
A, B, C IS_A set OF integer_constant;

A :== [1..10];
B :== [1,2,9,10];

C :== A - B; (* set difference, will contain 3,4,..8. *)

a[A] IS_A temperature;

n_C IS_A integer_constant;
n_C :== CARD[C];

T_avg_C IS_A temperature;
T_avg_C * n_C = SUM[a[i] | i IN C];

METHODS
METHOD on_load;
(* fix elements 1, 2, 9 and 10 *)
FIX a[B];

(* initialise those same elements to 290 K *)
FOR i IN B DO
a[i] := 290 {K};

END FOR;
(* initialise the remaining elements to 320 K *)
a[C] := 320 {K};

END on_load;
END mymodel;</source>

Note the use of the [[SUM]] statement for looping through elements of a set and adding up the resulting expressions.

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