[LUCENE-8758] Class Field levelN is not populated correctly in QuadPrefixTree

• Type: Improvement
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 4.0, 5.0, 6.0, 7.0, 8.0
• Fix Version/s: 8.3
• Component/s: modules/spatial-extras
• Labels: beginner
• Lucene Fields: New
• Assignee: David Smiley
• Reporter: Dominic Page
• Created: 10/Apr/19 12:26
• Updated: 28/Aug/22 15:43
• Resolved: 30/Aug/19 14:44

Description

QuadPrefixTree in Lucene prepopulates these arrays:

levelW = new double[maxLevels];
levelH = new double[maxLevels];
levelS = new int[maxLevels];
levelN = new int[maxLevels];

Like this

for (int i = 1; i < levelW.length; i++) {
{{ levelW[i] = levelW[i - 1] / 2.0;}}
{{ levelH[i] = levelH[i - 1] / 2.0;}}
{{ levelS[i] = levelS[i - 1] * 2;}}
{{ levelN[i] = levelN[i - 1] * 4;}}
}

The field

levelN[]

overflows after level 14 = 1073741824 where maxLevels is limited to 

MAX_LEVELS_POSSIBLE = 50;

The field levelN appears not to be used anywhere. Likewise, the field

{{levelS[] }}

is only used in the 

printInfo

method. I would propose either to remove both 

levelN[],levelS[]

or to change the datatype

levelN = new long[maxLevels];