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Compute stats for RoaringBoolArray (#874)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,162 @@ | ||
| use std::collections::HashMap; | ||
|
|
||
| use croaring::Bitset; | ||
| use vortex::stats::{ArrayStatisticsCompute, Stat, StatsSet}; | ||
| use vortex_error::{vortex_err, VortexResult}; | ||
|
|
||
| use crate::RoaringBoolArray; | ||
|
|
||
| impl ArrayStatisticsCompute for RoaringBoolArray { | ||
| fn compute_statistics(&self, stat: Stat) -> VortexResult<StatsSet> { | ||
| if self.is_empty() { | ||
| return Ok(StatsSet::new()); | ||
| } | ||
|
|
||
| // Only needs to compute IsSorted, IsStrictSorted and RunCount all other stats have been populated on construction | ||
| let bitmap = self.bitmap(); | ||
| BitmapStats( | ||
| bitmap | ||
| .to_bitset() | ||
| .ok_or_else(|| vortex_err!("Bitmap to Bitset conversion run out of memory"))?, | ||
| self.len(), | ||
| bitmap.statistics().cardinality, | ||
| ) | ||
| .compute_statistics(stat) | ||
| } | ||
| } | ||
|
|
||
| // Underlying bitset, length in bits, cardinality (true count) of the bitset | ||
| struct BitmapStats(Bitset, usize, u64); | ||
|
|
||
| impl ArrayStatisticsCompute for BitmapStats { | ||
| fn compute_statistics(&self, _stat: Stat) -> VortexResult<StatsSet> { | ||
| let bitset_slice = self.0.as_slice(); | ||
| // This is a weird case where the bitset is full of false values | ||
| // sometimes it will not allocate any underlying storage | ||
| // TODO(robert): This likely can be simplified after https://github.com/RoaringBitmap/CRoaring/issues/660 | ||
| if bitset_slice.is_empty() { | ||
| return Ok(StatsSet::from(HashMap::from([ | ||
| (Stat::IsSorted, true.into()), | ||
| (Stat::IsStrictSorted, (self.1 == 1).into()), | ||
| (Stat::RunCount, 1.into()), | ||
| ]))); | ||
| } | ||
|
|
||
| let whole_chunks = self.1 / 64; | ||
| let last_chunk_len = self.1 % 64; | ||
| let fist_bool = bitset_slice[0] & 1 == 1; | ||
| let mut stats = RoaringBoolStatsAccumulator::new(fist_bool); | ||
| for bits64 in bitset_slice[0..whole_chunks].iter() { | ||
| stats.next(*bits64); | ||
| } | ||
| stats.next_up_to_length(bitset_slice[whole_chunks], last_chunk_len); | ||
| Ok(stats.finish(self.2)) | ||
| } | ||
| } | ||
|
|
||
| struct RoaringBoolStatsAccumulator { | ||
| prev: bool, | ||
| is_sorted: bool, | ||
| run_count: usize, | ||
| len: usize, | ||
| } | ||
|
|
||
| impl RoaringBoolStatsAccumulator { | ||
| fn new(first_value: bool) -> Self { | ||
| Self { | ||
| prev: first_value, | ||
| is_sorted: true, | ||
| run_count: 1, | ||
| len: 0, | ||
| } | ||
| } | ||
|
|
||
| pub fn next_up_to_length(&mut self, next: u64, len: usize) { | ||
| assert!(len <= 64); | ||
| self.len += len; | ||
| for i in 0..len { | ||
| let current = ((next >> i) & 1) == 1; | ||
| // Booleans are sorted true > false so we aren't sorted if we switched from true to false value | ||
| if !current && self.prev { | ||
| self.is_sorted = false; | ||
| } | ||
| if current != self.prev { | ||
| self.run_count += 1; | ||
| self.prev = current; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| pub fn next(&mut self, next: u64) { | ||
| self.next_up_to_length(next, 64) | ||
| } | ||
|
|
||
| pub fn finish(self, cardinality: u64) -> StatsSet { | ||
| StatsSet::from(HashMap::from([ | ||
| (Stat::IsSorted, self.is_sorted.into()), | ||
| ( | ||
| Stat::IsStrictSorted, | ||
| (self.is_sorted && (self.len < 2 || (self.len == 2 && cardinality == 1))).into(), | ||
| ), | ||
| (Stat::RunCount, self.run_count.into()), | ||
| ])) | ||
| } | ||
| } | ||
|
|
||
| #[cfg(test)] | ||
|
|
||
| mod test { | ||
| use vortex::array::BoolArray; | ||
| use vortex::stats::ArrayStatistics; | ||
| use vortex::IntoArray; | ||
|
|
||
| use crate::RoaringBoolArray; | ||
|
|
||
| #[test] | ||
| #[cfg_attr(miri, ignore)] | ||
| fn bool_stats() { | ||
| let bool_arr = RoaringBoolArray::encode( | ||
| BoolArray::from(vec![false, false, true, true, false, true, true, false]).into_array(), | ||
| ) | ||
| .unwrap(); | ||
| assert!(!bool_arr.statistics().compute_is_strict_sorted().unwrap()); | ||
| assert!(!bool_arr.statistics().compute_is_sorted().unwrap()); | ||
| assert!(!bool_arr.statistics().compute_is_constant().unwrap()); | ||
| assert!(!bool_arr.statistics().compute_min::<bool>().unwrap()); | ||
| assert!(bool_arr.statistics().compute_max::<bool>().unwrap()); | ||
| assert_eq!(bool_arr.statistics().compute_run_count().unwrap(), 5); | ||
| assert_eq!(bool_arr.statistics().compute_true_count().unwrap(), 4); | ||
| } | ||
|
|
||
| #[test] | ||
| #[cfg_attr(miri, ignore)] | ||
| fn strict_sorted() { | ||
| let bool_arr_1 = | ||
| RoaringBoolArray::encode(BoolArray::from(vec![false, true]).into_array()).unwrap(); | ||
| assert!(bool_arr_1.statistics().compute_is_strict_sorted().unwrap()); | ||
| assert!(bool_arr_1.statistics().compute_is_sorted().unwrap()); | ||
|
|
||
| // TODO(robert): Reenable after https://github.com/RoaringBitmap/CRoaring/issues/660 is resolved | ||
| // let bool_arr_2 = | ||
| // RoaringBoolArray::encode(BoolArray::from(vec![true]).into_array()).unwrap(); | ||
| // assert!(bool_arr_2.statistics().compute_is_strict_sorted().unwrap()); | ||
| // assert!(bool_arr_2.statistics().compute_is_sorted().unwrap()); | ||
|
|
||
| let bool_arr_3 = | ||
| RoaringBoolArray::encode(BoolArray::from(vec![false]).into_array()).unwrap(); | ||
| assert!(bool_arr_3.statistics().compute_is_strict_sorted().unwrap()); | ||
| assert!(bool_arr_3.statistics().compute_is_sorted().unwrap()); | ||
|
|
||
| // TODO(robert): Reenable after https://github.com/RoaringBitmap/CRoaring/issues/660 is resolved | ||
| // let bool_arr_4 = | ||
| // RoaringBoolArray::encode(BoolArray::from(vec![true, false]).into_array()).unwrap(); | ||
| // assert!(!bool_arr_4.statistics().compute_is_strict_sorted().unwrap()); | ||
| // assert!(!bool_arr_4.statistics().compute_is_sorted().unwrap()); | ||
|
|
||
| let bool_arr_5 = | ||
| RoaringBoolArray::encode(BoolArray::from(vec![false, true, true]).into_array()) | ||
| .unwrap(); | ||
| assert!(!bool_arr_5.statistics().compute_is_strict_sorted().unwrap()); | ||
| assert!(bool_arr_5.statistics().compute_is_sorted().unwrap()); | ||
| } | ||
| } |