drupol /
phpermutations
| @@ 114-138 (lines=25) @@ | ||
| 111 | return $position; |
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| 112 | } |
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| 113 | ||
| 114 | function hilbert_to_point($hilbert, $order) { |
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| 115 | $current_square = "a"; |
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| 116 | $amount = 1 << $order - 1; |
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| 117 | $x = $y = 0; |
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| 118 | for ($i = 2 * $order; $i > 0; $i -= 2) { |
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| 119 | list ($position, $current_square) = $this->rev_map[$current_square][$hilbert >> $i - 2]; |
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| 120 | switch ($position) { |
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| 121 | case 1: |
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| 122 | $x += $amount; |
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| 123 | break; |
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| 124 | case 2: |
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| 125 | $y += $amount; |
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| 126 | break; |
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| 127 | case 3: |
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| 128 | $y += $amount; |
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| 129 | $x += $amount; |
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| 130 | break; |
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| 131 | default: |
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| 132 | break; |
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| 133 | } |
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| 134 | $amount /= 2; |
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| 135 | $hilbert &= (1 << ($i - 2)) - 1; |
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| 136 | } |
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| 137 | return [$x, $y]; |
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| 138 | } |
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| 139 | ||
| 140 | ||
| 141 | function xy2d($x, $y, $order = 16) { |
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| @@ 156-180 (lines=25) @@ | ||
| 153 | return $position; |
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| 154 | } |
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| 155 | ||
| 156 | function d2xy($hilbert, $order = 16) { |
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| 157 | $current_square = "a"; |
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| 158 | $amount = 1 << $order - 1; |
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| 159 | $x = $y = 0; |
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| 160 | for ($i = 2 * $order; $i > 0; $i -= 2) { |
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| 161 | list ($position, $current_square) = $this->rev_map[$current_square][$hilbert >> $i - 2]; |
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| 162 | switch ($position) { |
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| 163 | case 1: |
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| 164 | $x += $amount; |
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| 165 | break; |
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| 166 | case 2: |
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| 167 | $y += $amount; |
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| 168 | break; |
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| 169 | case 3: |
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| 170 | $y += $amount; |
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| 171 | $x += $amount; |
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| 172 | break; |
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| 173 | default: |
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| 174 | break; |
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| 175 | } |
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| 176 | $amount /= 2; |
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| 177 | $hilbert &= (1 << ($i - 2)) - 1; |
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| 178 | } |
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| 179 | return [$x, $y]; |
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| 180 | } |
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| 181 | ||
| 182 | function test_pth() { |
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| 183 | foreach (range(7, 0, -1) as $x) { |
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