File size: 5,416 Bytes
58629f0
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
c7e44c9
 
 
 
 
 
 
 
 
c4d6746
 
c7e44c9
 
c4d6746
 
 
c7e44c9
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ee1c835
c7e44c9
 
 
 
 
0e30c54
c7e44c9
 
 
 
 
0e30c54
c7e44c9
 
 
 
ee1c835
c7e44c9
ee1c835
 
c7e44c9
 
 
 
c4d6746
ee1c835
 
 
c7e44c9
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
c4d6746
c7e44c9
 
 
 
c4d6746
c7e44c9
 
 
 
 
c4d6746
c7e44c9
 
c4d6746
 
c7e44c9
 
 
 
 
 
 
 
c4d6746
 
 
 
 
 
 
 
 
 
 
c7e44c9
c4d6746
 
c7e44c9
bd0b4a3
 
 
 
c4d6746
bd0b4a3
 
 
 
 
 
c4d6746
bd0b4a3
 
 
 
 
 
 
c7e44c9
 
 
 
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
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
# Copyright 2023 Dmitry Ustalov
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

__author__ = 'Dmitry Ustalov'
__license__ = 'Apache 2.0'

import typing

import gradio as gr
import numpy as np
import numpy.typing as npt
import pandas as pd


# https://gist.github.com/dustalov/41678b70c40ba5a55430fa5e77b121d9#file-newman-py
def aggregate(wins: npt.NDArray[np.int64], ties: npt.NDArray[np.int64],
              seed: int = 0, tolerance: float = 10e-6, limit: int = 20) -> npt.ArrayLike:
    assert wins.shape == ties.shape, 'wins and ties shapes are different'

    rng = np.random.default_rng(seed)

    pi, v = rng.random(wins.shape[0]), rng.random()

    converged, iterations = False, 0

    while not converged:
        iterations += 1

        v_numerator = np.sum(
            ties * (pi[:, None] + pi) / (pi[:, None] + pi + 2 * v * np.sqrt(pi[:, None] * pi))
        ) / 2

        v_denominator = np.sum(
            wins * 2 * np.sqrt(pi[:, None] * pi) / (pi[:, None] + pi + 2 * v * np.sqrt(pi[:, None] * pi))
        )

        v = v_numerator / v_denominator
        v = np.nan_to_num(v, copy=False, nan=tolerance)

        pi_old = pi.copy()

        pi_numerator = np.sum(
            (wins + ties / 2) * (pi + v * np.sqrt(pi[:, np.newaxis] * pi)) /
            (pi[:, np.newaxis] + pi + 2 + v * np.sqrt(pi[:, np.newaxis] * pi)),
            axis=1
        )

        pi_denominator = np.sum(
            (wins + ties / 2) * (1 + v * np.sqrt(pi[:, np.newaxis] * pi)) /
            (pi[:, np.newaxis] + pi + 2 + v * np.sqrt(pi[:, np.newaxis] * pi)),
            axis=0
        )

        pi = pi_numerator / pi_denominator
        pi = np.nan_to_num(pi, copy=False, nan=tolerance)

        converged = np.allclose(pi / (pi + 1), pi_old / (pi_old + 1),
                                rtol=tolerance, atol=tolerance) or (iterations >= limit)

    return pi


def handler(file: typing.IO[bytes], seed: int) -> pd.DataFrame:
    if file is None:
        raise gr.Error('File must be uploaded')

    try:
        df = pd.read_csv(file.name, dtype=str)
    except ValueError as e:
        raise gr.Error(f'Parsing error: {e}')

    if not pd.Series(['left', 'right', 'winner']).isin(df.columns).all():
        raise gr.Error('Columns must exist: left, right, winner')

    if not df['winner'].isin(pd.Series(['left', 'right', 'tie'])).all():
        raise gr.Error('Allowed winner values: left, right, tie')

    df = df[['left', 'right', 'winner']]

    df.dropna(axis='rows', inplace=True)

    index = pd.Index(np.unique(df[['left', 'right']].values), name='item')

    df_wins = pd.pivot_table(df[df['winner'].isin(['left', 'right'])],
                             index='left', columns='right', values='winner',
                             aggfunc='count', fill_value=0)
    df_wins = df_wins.reindex(labels=index, columns=index, fill_value=0, copy=False)

    df_ties = pd.pivot_table(df[df['winner'] == 'tie'],
                             index='left', columns='right', values='winner', aggfunc='count',
                             fill_value=0)
    df_ties = df_ties.reindex(labels=index, columns=index, fill_value=0, copy=False)

    wins = df_wins.to_numpy(dtype=np.int64)
    ties = df_ties.to_numpy(dtype=np.int64)
    ties += ties.T

    scores = aggregate(wins, ties, seed=seed)

    df_result = pd.DataFrame(data={'score': scores}, index=index)
    df_result['rank'] = df_result['score'].rank(na_option='bottom', ascending=False).astype(int)
    df_result.fillna(np.NINF, inplace=True)
    df_result.sort_values(by=['rank', 'score'], ascending=[True, False], inplace=True)
    df_result.reset_index(inplace=True)

    return df_result


iface = gr.Interface(
    fn=handler,
    inputs=[
        gr.File(
            value='example.csv',
            file_types=['.tsv', '.csv'],
            label='Comparisons'
        ),
        gr.Number(
            label='Seed',
            precision=0
        )
    ],
    outputs=gr.Dataframe(
        headers=['item', 'score', 'rank'],
        label='Ranking'
    ),
    title='Turn Your Side-by-Side Comparisons into Ranking!',
    description='''
This easy-to-use tool transforms pairwise comparisons (aka side-by-side) to a meaningful ranking of items.

As an input, it expects a comma-separated (CSV) file with a header containing the following columns:

- `left`: the first compared item
- `right`: the second compared item
- `winner`: the label indicating the winning item

Possible values for `winner` are `left`, `right`, or `tie`.
The provided example might be a good starting point.

As the output, this tool provides a table with items, their estimated scores, and ranks.
    ''',
    article='''
This tool implements the tie-aware ranking aggregation algorithm as described in
[Efficient Computation of Rankings from Pairwise Comparisons](https://www.jmlr.org/papers/v24/22-1086.html).
    ''',
    allow_flagging='never'
)

iface.launch()