core_question\engine\variants\least_used_strategy Class Reference

A question_variant_selection_strategy that randomly selects variants that were not used yet. More...

Inheritance diagram for core_question\engine\variants\least_used_strategy:

Public Member Functions
	__construct (\question_usage_by_activity $quba, qubaid_condition $qubaids)
	Constructor. More...
	choose_variant ($maxvariants, $seed)

Protected Attributes
array	$selectedvariant = array()
	seed => variant number.
array	$variantsusecounts = array()
	seed => variant number => number of uses.

Detailed Description

A question_variant_selection_strategy that randomly selects variants that were not used yet.

If all variants have been used at least once in the set of usages under consideration, then then it picks one of the least often used.

Within one particular use of this class, each seed will always select the same variant. This is so that shared datasets work in calculated questions, and similar features in question types like varnumeric and STACK.

Copyright

2015 The Open University

License

http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Constructor & Destructor Documentation

__construct()

core_question\engine\variants\least_used_strategy::__construct	(	\question_usage_by_activity	$quba,
		qubaid_condition	$qubaids
	)

Constructor.

Parameters

question_usage_by_activity	$quba	the question usage we will be picking variants for.
qubaid_condition	$qubaids	ids of the usages to consider when counting previous uses of each variant.

Member Function Documentation

choose_variant()

core_question\engine\variants\least_used_strategy::choose_variant	(		$maxvariants,
			$seed
	)

Parameters

int	$maxvariants	the num
string	$seed	data that can be used to controls how the variant is selected in a semi-random way.

Return values

int	the variant to use, a number betweeb 1 and $maxvariants inclusive.

Implements question_variant_selection_strategy.

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

• question/classes/engine/variants/least_used_strategy.php