Mercator/ironsea_index_sfc_dbc
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Reduce reallocation of vectors.

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This commit is contained in:
Lionel Sambuc
2019-10-08 11:52:33 +02:00
parent 49f4462b36
commit ad9339f53d
1 changed files with 4 additions and 4 deletions
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8
src/cell_space.rs
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@@ -24,9 +24,6 @@ where
T: Table<R>, T: Table<R>,
R: Record<K> + Debug, R: Record<K> + Debug,
{ {
// Do not forget to initialise cells[0]
let mut cells: Vec<Cell<V>> = vec![vec![]];
// 1. Retrieve a list of distinct values for the coordinate `dimension` // 1. Retrieve a list of distinct values for the coordinate `dimension`
let mut distinct = vec![]; let mut distinct = vec![];
let records = table.get_table(); let records = table.get_table();
@@ -57,13 +54,16 @@ where
// result as this is the max number of elements per bucket. // result as this is the max number of elements per bucket.
let max_offset = (distinct.len() / (1 << cell_bits)) + 1; let max_offset = (distinct.len() / (1 << cell_bits)) + 1;
// Do not forget to initialise cells[0]
let mut cells: Vec<Cell<V>> = Vec::with_capacity(1 << cell_bits);
for coordinate in distinct { for coordinate in distinct {
//trace!("{:?} {:?} {:?} {:?}", dimension, coordinate, cell, count); //trace!("{:?} {:?} {:?} {:?}", dimension, coordinate, cell, count);
if count == max_offset { if count == max_offset {
count = 0; count = 0;
cell += 1; cell += 1;
cells.push(vec![]); cells.push(Vec::with_capacity(max_offset));
} }
cells[cell].push(coordinate); cells[cell].push(coordinate);