SHOW:
|
|
- or go back to the newest paste.
1 | - | //submatrix first version |
1 | + | //submatrix second version |
2 | ||
3 | - | constexpr Matrix2 submatrix(const Matrix3& m, Matrix3::size_type row_, Matrix3::size_type column_) { |
3 | + | constexpr value_type operator[](size_type i) const noexcept { |
4 | - | assert(row_ < m.rows() && column_ < m.columns() && "invalid submatrix specification. row and column must be inside the input matrix."); |
4 | + | assert(i < size()); |
5 | - | using size_type = Matrix3::size_type; |
5 | + | return _data[i]; |
6 | - | Matrix2 r; |
6 | + | |
7 | - | size_type i = 0; |
7 | + | constexpr reference operator[](size_type i) noexcept { |
8 | - | for (size_type k = 0; k < m.rows(); k++) { |
8 | + | assert(i < size()); |
9 | - | if (k == row_) { |
9 | + | return _data[i]; |
10 | - | continue; |
10 | + | |
11 | ||
12 | - | size_type j = 0; |
12 | + | constexpr size_type index_to_column(size_type index) const noexcept { |
13 | - | for (size_type l = 0; l < m.columns(); l++) { |
13 | + | assert(index < size()); |
14 | - | if (l == column_) { |
14 | + | return index % columns(); |
15 | - | continue; |
15 | + | |
16 | - | } |
16 | + | constexpr size_type index_to_row(size_type index) const noexcept { |
17 | - | r(i, j) = m(k, l); |
17 | + | assert(index < size()); |
18 | - | j++; |
18 | + | return index / columns(); |
19 | } | |
20 | - | i++; |
20 | + | |
21 | - | } |
21 | + | constexpr auto submatrix(size_type remove_row, size_type remove_column) const noexcept { |
22 | assert(remove_row < rows() && remove_column < columns() && "submatrix: row and column to remove must be inside the original matrix."); | |
23 | Matrix<ROWS - 1, COLUMNS - 1> r; | |
24 | uint8_t ri = 0; | |
25 | for (size_type i = 0; i < size(); i++) { | |
26 | if(index_to_row(i) != remove_row && index_to_column(i) != remove_column) { | |
27 | r[ri++] = _data[i]; | |
28 | } | |
29 | } | |
30 | return r; | |
31 | } | |
32 | ||
33 | TEST(Matrix, getRowFromIndex) { | |
34 | const Matrix3 a{ | |
35 | 1,5,0, | |
36 | -3,2,7, | |
37 | 0,6,-3 | |
38 | }; | |
39 | EXPECT_EQ(0, a.index_to_row(0)); | |
40 | EXPECT_EQ(0, a.index_to_row(2)); | |
41 | EXPECT_EQ(2, a.index_to_row(6)); | |
42 | EXPECT_EQ(2, a.index_to_row(8)); | |
43 | } | |
44 | ||
45 | TEST(Matrix, getColumnFromIndex) { | |
46 | const Matrix3 a{ | |
47 | 1,5,0, | |
48 | -3,2,7, | |
49 | 0,6,-3 | |
50 | }; | |
51 | EXPECT_EQ(0, a.index_to_column(0)); | |
52 | EXPECT_EQ(1, a.index_to_column(1)); | |
53 | EXPECT_EQ(2, a.index_to_column(2)); | |
54 | EXPECT_EQ(0, a.index_to_column(6)); | |
55 | EXPECT_EQ(1, a.index_to_column(7)); | |
56 | EXPECT_EQ(2, a.index_to_column(8)); | |
57 | } | |
58 | ||
59 | TEST(Matrix, submatrixOf3x3is2x2) { | |
60 | const Matrix3 a{ | |
61 | 1,5,0, | |
62 | -3,2,7, | |
63 | 0,6,-3 | |
64 | }; | |
65 | const Matrix2 truth{ | |
66 | -3, 2, | |
67 | 0, 6 | |
68 | }; | |
69 | const auto b = submatrix(a, 0, 2); | |
70 | const auto c = a.submatrix(0, 2); | |
71 | EXPECT_TRUE(b == truth); | |
72 | EXPECT_TRUE(c == truth); | |
73 | } |