geos::index::quadtree::IntervalSize Class Reference

Provides a test for whether an interval is so small it should be considered as zero for the purposes of inserting it into a binary tree. More...

#include <geos/indexQuadtree.h>

List of all members.

Static Public Member Functions
static bool	isZeroWidth (double min, double max)
Static Public Attributes
static const int	MIN_BINARY_EXPONENT = -50

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Detailed Description

Provides a test for whether an interval is so small it should be considered as zero for the purposes of inserting it into a binary tree.

The reason this check is necessary is that round-off error can cause the algorithm used to subdivide an interval to fail, by computing a midpoint value which does not lie strictly between the endpoints.

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Member Data Documentation

const int geos::index::quadtree::IntervalSize::MIN_BINARY_EXPONENT = -50 [static]

This value is chosen to be a few powers of 2 less than the number of bits available in the double representation (i.e. 53). This should allow enough extra precision for simple computations to be correct, at least for comparison purposes.

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

• IntervalSize.h