src/types/matrix.cpp

changeset 1037
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1036:993c46d7eb75 1037:4a9185e94d78
1 /*
2 * LDForge: LDraw parts authoring CAD
3 * Copyright (C) 2013 - 2016 Teemu Piippo
4 *
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18
19 #include "../basics.h"
20 #include "../format.h"
21 #include "matrix.h"
22
23 /**
24 * @brief Matrix::Matrix
25 * Default-constructor for a matrix -- does not actually initialize the member values.
26 */
27 Matrix::Matrix() {}
28
29 /**
30 * @brief Matrix::Matrix
31 * @param values
32 * Initializes the matrix from a C array
33 * Note: the array must have (at least) 9 values!
34 */
35 Matrix::Matrix (double values[])
36 {
37 for (int i = 0; i < 9; ++i)
38 m_values[i] = values[i];
39 }
40
41 /**
42 * @brief Matrix::Matrix
43 * @param fillvalue
44 * Constructs a matrix from a single fill value.
45 */
46 Matrix::Matrix (double fillvalue)
47 {
48 for (int i = 0; i < 9; ++i)
49 m_values[i] = fillvalue;
50 }
51
52 /**
53 * @brief Matrix::Matrix
54 * @param values
55 * Constructs a matrix from an initializer list.
56 * Note: the initializer list must have exactly 9 values.
57 */
58 Matrix::Matrix (const std::initializer_list<double>& values)
59 {
60 if (values.size() == 9)
61 memcpy (&m_values[0], values.begin(), sizeof m_values);
62 }
63
64 /**
65 * @brief Matrix::dump
66 * Prints the matrix out.
67 */
68 void Matrix::dump() const
69 {
70 for (int i = 0; i < 3; ++i)
71 {
72 for (int j = 0; j < 3; ++j)
73 print ("%1\t", m_values[i * 3 + j]);
74
75 print ("\n");
76 }
77 }
78
79 /**
80 * @brief Matrix::toString
81 * @return a string representation of the matrix
82 */
83 QString Matrix::toString() const
84 {
85 QString val;
86
87 for (int i = 0; i < 9; ++i)
88 {
89 if (i > 0)
90 val += ' ';
91
92 val += QString::number (m_values[i]);
93 }
94
95 return val;
96 }
97
98 /**
99 * @brief Matrix::zero
100 * Fills the matrix with zeros
101 */
102 void Matrix::zero()
103 {
104 memset (&m_values[0], 0, sizeof m_values);
105 }
106
107 /**
108 * @brief Matrix::multiply
109 * @param other
110 * @return this matrix multiplied with @c other.
111 * @note @c a.mult(b) is not equivalent to @c b.mult(a)
112 */
113 Matrix Matrix::multiply (const Matrix& other) const
114 {
115 Matrix result;
116 result.zero();
117
118 for (int i = 0; i < 3; ++i)
119 for (int j = 0; j < 3; ++j)
120 for (int k = 0; k < 3; ++k)
121 result[(i * 3) + j] += m_values[(i * 3) + k] * other[(k * 3) + j];
122
123 return result;
124 }
125
126 /**
127 * @brief Matrix::determinant
128 * @return the matrix's determinant
129 */
130 double Matrix::determinant() const
131 {
132 return (value (0) * value (4) * value (8)) +
133 (value (1) * value (5) * value (6)) +
134 (value (2) * value (3) * value (7)) -
135 (value (2) * value (4) * value (6)) -
136 (value (1) * value (3) * value (8)) -
137 (value (0) * value (5) * value (7));
138 }
139
140 /**
141 * @brief Matrix::operator ==
142 * @param other
143 * @return whether the two matrices are equal
144 */
145 bool Matrix::operator==(const Matrix& other) const
146 {
147 for (int i = 0; i < countof(m_values); ++i)
148 {
149 if (not qFuzzyCompare(m_values[i], other.m_values[i]))
150 return false;
151 }
152 return true;
153 }
154
155 /**
156 * @brief Matrix::operator !=
157 * @param other
158 * @return whether the two matrices are not equal
159 */
160 bool Matrix::operator!=(const Matrix& other) const
161 {
162 return not operator==(other);
163 }
164

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