| 1 |
efrain |
1 |
<?php
|
|
|
2 |
// This file is part of Moodle - http://moodle.org/
|
|
|
3 |
//
|
|
|
4 |
// Moodle is free software: you can redistribute it and/or modify
|
|
|
5 |
// it under the terms of the GNU General Public License as published by
|
|
|
6 |
// the Free Software Foundation, either version 3 of the License, or
|
|
|
7 |
// (at your option) any later version.
|
|
|
8 |
//
|
|
|
9 |
// Moodle is distributed in the hope that it will be useful,
|
|
|
10 |
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
11 |
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
12 |
// GNU General Public License for more details.
|
|
|
13 |
//
|
|
|
14 |
// You should have received a copy of the GNU General Public License
|
|
|
15 |
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
|
|
|
16 |
|
|
|
17 |
/**
|
|
|
18 |
* Binary classifier target.
|
|
|
19 |
*
|
|
|
20 |
* @package core_analytics
|
|
|
21 |
* @copyright 2017 David Monllao {@link http://www.davidmonllao.com}
|
|
|
22 |
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
|
|
|
23 |
*/
|
|
|
24 |
|
|
|
25 |
namespace core_analytics\local\target;
|
|
|
26 |
|
|
|
27 |
defined('MOODLE_INTERNAL') || die();
|
|
|
28 |
|
|
|
29 |
/**
|
|
|
30 |
* Binary classifier target.
|
|
|
31 |
*
|
|
|
32 |
* @package core_analytics
|
|
|
33 |
* @copyright 2017 David Monllao {@link http://www.davidmonllao.com}
|
|
|
34 |
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
|
|
|
35 |
*/
|
|
|
36 |
abstract class binary extends discrete {
|
|
|
37 |
|
|
|
38 |
/**
|
|
|
39 |
* is_linear
|
|
|
40 |
*
|
|
|
41 |
* @return bool
|
|
|
42 |
*/
|
|
|
43 |
public function is_linear() {
|
|
|
44 |
return false;
|
|
|
45 |
}
|
|
|
46 |
|
|
|
47 |
/**
|
|
|
48 |
* Returns the target discrete values.
|
|
|
49 |
*
|
|
|
50 |
* Only useful for targets using discrete values, must be overwriten if it is the case.
|
|
|
51 |
*
|
|
|
52 |
* @return array
|
|
|
53 |
*/
|
|
|
54 |
final public static function get_classes() {
|
|
|
55 |
return array(0, 1);
|
|
|
56 |
}
|
|
|
57 |
|
|
|
58 |
/**
|
|
|
59 |
* Returns the predicted classes that will be ignored.
|
|
|
60 |
*
|
|
|
61 |
* @return array
|
|
|
62 |
*/
|
|
|
63 |
public function ignored_predicted_classes() {
|
|
|
64 |
// Zero-value class is usually ignored in binary classifiers.
|
|
|
65 |
return array(0);
|
|
|
66 |
}
|
|
|
67 |
|
|
|
68 |
/**
|
|
|
69 |
* Is the calculated value a positive outcome of this target?
|
|
|
70 |
*
|
|
|
71 |
* @param string $value
|
|
|
72 |
* @param string $ignoredsubtype
|
|
|
73 |
* @return int
|
|
|
74 |
*/
|
|
|
75 |
public function get_calculation_outcome($value, $ignoredsubtype = false) {
|
|
|
76 |
|
|
|
77 |
if (!self::is_a_class($value)) {
|
|
|
78 |
throw new \moodle_exception('errorpredictionformat', 'analytics');
|
|
|
79 |
}
|
|
|
80 |
|
|
|
81 |
if (in_array($value, $this->ignored_predicted_classes(), false)) {
|
|
|
82 |
// Just in case, if it is ignored the prediction should not even be recorded but if it would, it is ignored now,
|
|
|
83 |
// which should mean that is it nothing serious.
|
|
|
84 |
return self::OUTCOME_VERY_POSITIVE;
|
|
|
85 |
}
|
|
|
86 |
|
|
|
87 |
// By default binaries are danger when prediction = 1.
|
|
|
88 |
if ($value) {
|
|
|
89 |
return self::OUTCOME_VERY_NEGATIVE;
|
|
|
90 |
}
|
|
|
91 |
return self::OUTCOME_VERY_POSITIVE;
|
|
|
92 |
}
|
|
|
93 |
|
|
|
94 |
/**
|
|
|
95 |
* classes_description
|
|
|
96 |
*
|
|
|
97 |
* @return string[]
|
|
|
98 |
*/
|
|
|
99 |
protected static function classes_description() {
|
|
|
100 |
return array(
|
|
|
101 |
get_string('yes'),
|
|
|
102 |
get_string('no')
|
|
|
103 |
);
|
|
|
104 |
}
|
|
|
105 |
|
|
|
106 |
}
|