-
Notifications
You must be signed in to change notification settings - Fork 30
/
Algebraic.php
106 lines (93 loc) · 2.25 KB
/
Algebraic.php
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
<?php
/**
* Copyright (C) 2023 Graham Breach
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* For more information, please contact <graham@goat1000.com>
*/
namespace Goat1000\SVGGraph;
/**
* Class for algebraic functions
*/
class Algebraic {
private $type = 'straight';
private $coeffs = [0, 1];
public function __construct($type)
{
$this->type = $type;
}
/**
* Sets the coefficients in order, lowest power first
*/
public function setCoefficients(array $coefficients)
{
$this->coeffs = $coefficients;
}
/**
* Returns the y value for a + bx + cx^2 ...
*/
public function __invoke($x)
{
$val = 0;
foreach($this->coeffs as $p => $c) {
switch($p) {
case 0: $val = bcadd($val, $c);
break;
case 1: $val = bcadd($val, bcmul($c, $x));
break;
default:
$val = bcadd($val, bcmul($c, bcpow($x, $p)));
break;
}
}
return $val;
}
/**
* Creates a row of the vandermonde matrix
*/
public function vandermonde($x)
{
$t = $this->type;
return $this->{$t}($x);
}
private function straight($x)
{
return [$x];
}
private function quadratic($x)
{
return [$x, bcmul($x, $x)];
}
private function cubic($x)
{
$res = [$x, bcmul($x, $x)];
$res[] = bcmul($res[1], $x);
return $res;
}
private function quartic($x)
{
$res = $this->cubic($x);
$res[] = bcmul($res[1], $res[1]);
return $res;
}
private function quintic($x)
{
$res = $this->cubic($x);
$res[] = bcmul($res[1], $res[1]);
$res[] = bcmul($res[1], $res[2]);
return $res;
}
}