CmpMaxOrTerms Struct Reference

Class providing an operator which sorts postlists to select max or terms. More...

List of all members.

Public Member Functions
bool	operator() (const PostList *a, const PostList *b)
	Return true if and only if a has a strictly greater termweight than b; with the proviso that if the termfrequency of a or b is 0, then the termweight is considered to be 0.

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Detailed Description

Class providing an operator which sorts postlists to select max or terms.

This returns true if a has a (strictly) greater termweight than b, unless a or b contain no documents, in which case the other one is selected.

Definition at line 236 of file queryoptimiser.cc.

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Member Function Documentation

bool CmpMaxOrTerms::operator()	(	const PostList *	a,
		const PostList *	b
	)			[inline]

Return true if and only if a has a strictly greater termweight than b; with the proviso that if the termfrequency of a or b is 0, then the termweight is considered to be 0.

We use termfreq_max() because we really don't want to exclude a postlist which has a low but non-zero termfrequency: the estimate is quite likely to be zero in this case.

Definition at line 245 of file queryoptimiser.cc.

References Xapian::PostingIterator::Internal::get_maxweight(), and Xapian::PostingIterator::Internal::get_termfreq_max().

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

• matcher/queryoptimiser.cc

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