vortex_array/arrays/primitive/array/
top_value.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright the Vortex contributors
3
4use std::hash::Hash;
5
6use rustc_hash::FxBuildHasher;
7use vortex_error::VortexExpect;
8use vortex_error::VortexResult;
9use vortex_mask::AllOr;
10use vortex_mask::Mask;
11use vortex_utils::aliases::hash_map::HashMap;
12
13use crate::LEGACY_SESSION;
14use crate::VortexSessionExecute;
15use crate::arrays::PrimitiveArray;
16use crate::arrays::primitive::NativeValue;
17use crate::dtype::NativePType;
18use crate::match_each_native_ptype;
19use crate::scalar::PValue;
20
21impl PrimitiveArray {
22    /// Compute most common present value of this array
23    pub fn top_value(&self) -> VortexResult<Option<(PValue, usize)>> {
24        if self.is_empty() {
25            return Ok(None);
26        }
27
28        if self.validity()?.definitely_all_null() {
29            return Ok(None);
30        }
31
32        match_each_native_ptype!(self.ptype(), |P| {
33            let (top, count) = typed_top_value(
34                self.as_slice::<P>(),
35                self.as_ref().validity()?.execute_mask(
36                    self.as_ref().len(),
37                    &mut LEGACY_SESSION.create_execution_ctx(),
38                )?,
39            );
40            Ok(Some((top.into(), count)))
41        })
42    }
43}
44
45fn typed_top_value<T>(values: &[T], mask: Mask) -> (T, usize)
46where
47    T: NativePType,
48    NativeValue<T>: Eq + Hash,
49{
50    let mut distinct_values: HashMap<NativeValue<T>, usize, FxBuildHasher> =
51        HashMap::with_hasher(FxBuildHasher);
52    match mask.indices() {
53        AllOr::All => {
54            for value in values.iter().copied() {
55                *distinct_values.entry(NativeValue(value)).or_insert(0) += 1;
56            }
57        }
58        AllOr::None => unreachable!("All invalid arrays should be handled earlier"),
59        AllOr::Some(idxs) => {
60            for &i in idxs {
61                *distinct_values
62                    .entry(NativeValue(unsafe { *values.get_unchecked(i) }))
63                    .or_insert(0) += 1
64            }
65        }
66    }
67
68    let (&top_value, &top_count) = distinct_values
69        .iter()
70        .max_by_key(|&(_, &count)| count)
71        .vortex_expect("non-empty");
72    (top_value.0, top_count)
73}
vortex_array/arrays/primitive/array/top_value.rs

vortex_array/arrays/primitive/array/
top_value.rs
