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

vortex_array/arrays/primitive/array/
top_value.rs
