1mlpack_approx_kfn(1)        General Commands Manual       mlpack_approx_kfn(1)
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NAME

6       mlpack_approx_kfn - approximate furthest neighbor search
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SYNOPSIS

9        mlpack_approx_kfn [-h] [-v]
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DESCRIPTION

12       This  program  implements  two strategies for furthest neighbor search.
13       These strategies are:
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15              ·  The 'qdafn' algorithm from 'Approximate Furthest Neighbor  in
16                 High  Dimensions' by R. Pagh, F. Silvestri, J. Sivertsen, and
17                 M. Skala, in Similarity Search and Applications 2015 (SISAP).
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19              ·  The 'DrusillaSelect' algorithm from  'Fast  approximate  fur‐
20                 thest  neighbors  with data-dependent candidate selection, by
21                 R.R. Curtin and A.B. Gardner, in Similarity Search and Appli‐
22                 cations 2016 (SISAP).
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24       These two strategies give approximate results for the furthest neighbor
25       search problem and can be used as fast replacements for other  furthest
26       neighbor techniques such as those found in the mlpack_kfn program. Note
27       that typically, the 'ds' algorithm requires far fewer tables  and  pro‐
28       jections than the 'qdafn' algorithm.
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30       Specify a reference set (set to search in) with --reference_file, spec‐
31       ify a query set with --query_file,  and  specify  algorithm  parameters
32       with  --num_tables  (-t)  and  --num_projections  (-p)  (or  don't  and
33       defaults will be used). The algorithm to  be  used  (either  'ds'---the
34       default---or  'qdafn')  may be specified with --algorithm. Also specify
35       the number of neighbors to search for with --k. Each of  those  options
36       also has short names; see the detailed parameter documentation below.
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38       If  no  query  file is specified, the reference set will be used as the
39       query set. A model may be saved with --output_model_file (-M),  and  an
40       input  model  may  be loaded instead of specifying a reference set with
41       --input_model_file (-m).
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43       Results for each query point are  stored  in  the  files  specified  by
44       --neighbors_file  and  --distances_file.  This is in the same format as
45       the mlpack_kfn and mlpack_knn programs: each row holds the k  distances
46       or neighbor indices for each query point.
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OPTIONAL INPUT OPTIONS

49       --algorithm (-a) [string]
50              Algorithm to use: 'ds' or 'qdafn'. Default value 'ds'.
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52       --calculate_error (-e)
53              If  set, calculate the average distance error for the first fur‐
54              thest neighbor only.  --distances_file  (-d)  [string]  File  to
55              save   furthest   neighbor  distances  to.   Default  value  ''.
56              --exact_distances_file (-x) [string] File containing exact  dis‐
57              tances to furthest neighbors; this can be used to avoid explicit
58              calculation when --calculate_error is set.  Default value ''.
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60       --help (-h)
61              Default help info.
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63       --info [string]
64              Get help on a specific module  or  option.   Default  value  ''.
65              --input_model_file  (-m)  [string]  File containing input model.
66              Default value ''.
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68       --k (-k) [int]
69              Number of furthest neighbors to search for.   Default  value  0.
70              --neighbors_file  (-n)  [string]  File to save furthest neighbor
71              indices to.  Default value  ''.   --num_projections  (-p)  [int]
72              Number  of projections to use in each hash table.  Default value
73              5.
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75       --num_tables (-t) [int]
76              Number of hash tables to use. Default value 5.
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78       --query_file (-q) [string]
79              File  containing  query  points.  Default  value  ’'.   --refer‐
80              ence_file   (-r)  [string]  File  containing  reference  points.
81              Default value ’'.
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83       --verbose (-v)
84              Display informational messages and the full list  of  parameters
85              and timers at the end of execution.
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87       --version (-V)
88              Display the version of mlpack.
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OPTIONAL OUTPUT OPTIONS

91       --output_model_file (-M) [string] File to save output model to. Default
92       value ’'.
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ADDITIONAL INFORMATION

ADDITIONAL INFORMATION

96       For further information, including relevant papers, citations, and the‐
97       ory, For further information, including relevant papers, citations, and
98       theory, consult the documentation  found  at  http://www.mlpack.org  or
99       included    with    your    consult    the   documentation   found   at
100       http://www.mlpack.org or included with  your  DISTRIBUTION  OF  MLPACK.
101       DISTRIBUTION OF MLPACK.
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