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From "Uwe Schindler (JIRA)" <j...@apache.org>
Subject [jira] Assigned: (LUCENE-1541) Trie range - make trie range indexing more flexible
Date Tue, 17 Feb 2009 19:32:59 GMT

     [ https://issues.apache.org/jira/browse/LUCENE-1541?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Uwe Schindler reassigned LUCENE-1541:
-------------------------------------

    Assignee: Uwe Schindler

I prepare a patch.

Something to note: Choosing the correct precision step may be very difficult. E.g. for floats
and doubles, you must exactly know, how the ieee-754 bitmap looks like to be effective; this
is why I recommend for beginners to use a equidistant precision step. For normal integer values
or fixed point values (like prices in cents as long), it is more meaningful. For doubles/floats,
you must know, how many bits of the integer representation represent sign (1, thats simple),
exponent and mantissa. But for experts, it may be ok. I will change only the expert functions
to accept a array of precionStep values.

> Trie range - make trie range indexing more flexible
> ---------------------------------------------------
>
>                 Key: LUCENE-1541
>                 URL: https://issues.apache.org/jira/browse/LUCENE-1541
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: contrib/*
>            Reporter: Ning Li
>            Assignee: Uwe Schindler
>            Priority: Minor
>
> In the current trie range implementation, a single precision step is specified. With
a large precision step (say 8), a value is indexed in fewer terms (8) but the number of terms
for a range can be large. With a small precision step (say 2), the number of terms for a range
is smaller but a value is indexed in more terms (32).
> We want to add an option that different precision steps can be set for different precisions.
An expert can use this option to keep the number of terms for a range small and at the same
time index a value in a small number of terms. See the discussion in LUCENE-1470 that results
in this issue.

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