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See:
Description
Interface Summary | |
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DoubleQuantileFinder | The interface shared by all quantile finders, no matter if they are exact or approximate. |
Class Summary | |
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DoubleBuffer | A buffer holding double elements; internally used for computing approximate quantiles. |
DoubleEquiDepthHistogram | Read-only equi-depth histogram for selectivity estimation. |
DoubleQuantileFinderFactory | Factory constructing exact and approximate quantile finders for both known and unknown N. |
ExactDoubleQuantileFinder | Exact quantile finding algorithm for known and unknown N requiring large main memory; computes quantiles over a sequence of double elements. |
Scalable algorithms and data structures to compute approximate quantiles over very large data sequences. The approximation guarantees are explicit, and apply for arbitrary value distributions and arrival distributions of the dataset. The main memory requirements are smaller than for any other known technique by an order of magnitude.
The approx. algorithms are primarily intended to help applications scale. When faced with a large data sequence, traditional methods either need very large memories or time consuming disk based sorting. In constrast, the approx. algorithms can deal with > 10^10 values without disk based sorting.
All classes can be seen from various angles, for example as
DoubleQuantileFinderFactory
and the interface DoubleQuantileFinder
to learn more.
Most users will never need to know more than how to use these.
Actual implementations of the QuantileFinder interface are hidden.
They are indirectly constructed via the the factory.
QuantileDoubleBin1D
, demonstrating how this package can be used.
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