elinor 0.4.0

Evaluation Library in Information Retrieval
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35

use std::collections::BTreeMap;

use crate::PredScore;
use crate::Relevance;
use crate::TrueScore;

/// Computes the Bpref.
pub fn compute_bpref<K>(
    trues: &BTreeMap<K, TrueScore>,
    sorted_preds: &[Relevance<K, PredScore>],
    rel_lvl: TrueScore,
) -> f64
where
    K: Eq + Ord,
{
    let n_rels = trues.values().filter(|&&rel| rel >= rel_lvl).count() as f64;
    let n_non_rels = trues.len() as f64 - n_rels;

    let mut bpref = 0.0;
    let mut n_non_rels_so_far = 0.0_f64;

    for pred in sorted_preds {
        if let Some(&rel) = trues.get(&pred.doc_id) {
            if rel >= rel_lvl {
                bpref += 1.0 - n_non_rels_so_far.min(n_rels) / n_non_rels.min(n_rels);
            } else {
                n_non_rels_so_far += 1.0;
            }
        }
    }
    if n_rels != 0.0 {
        bpref /= n_rels
    }
    bpref
}