Update algorithm doc
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@ -12,71 +12,25 @@
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== Data format
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[source]
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[source,title='this_algorithm and S2 CellID Format']
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----
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Example: Face 2, level 23
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# Most significant 3 bits are for the face
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face_number = 0b010
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# This algorithm is always level 23
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data_bits = level * 2 = 23 * 2 = 46
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# The bit after the data bits is always 1
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# All subsequent bits are always 0
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Bit : 64 48 32 16 1
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=== this_algorithm Format ===
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WORD3 (13 bits) : vvvvvvvvvvvvv
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WORD2 (13 bits) : | |vvv vvvvvvvvvv
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WORD1 (13 bits) : | | |vvvvvv vvvvvvv
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0000 (10 bits) : | | | |vvvvvvvvv v
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Not represented : | | | | |
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: | | | | |
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Bit : 64 52 48 39 32 26 16 1
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: | | | | | | | |
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: 0100101110101000 1011100010010011 1001001100100l00 1100000000000000
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Face number : ^^^
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Data bits : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^
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Bit after data bits (1) : ^
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=== S2 CellID Format === | | || |
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Face number : ^^^ || |
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Data bits : ^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^ ^| |
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Bit after data bits (1) : ^ |
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All remaining bits (0) : ^^^^^^^^^^^^^^
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----
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[source]
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----
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All remaining bits (0) : vvvvvvvvvvvvvv
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Bit after data bits (1) : v
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Data bits : vvvvvvvvvvvvvvvvvvvvvvvvvvvvv vvvvvvvvvvvvvvvvv
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Face number : vvv
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Bit : 64 48 32 16 1
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: | | | | |
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: 01001011101010001011100010010011 1001001100100l001100000000000000
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Not represented : ^^^^^^^^^^^^^^^
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0000 (10 bits) : ^^^^^^^^^^
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WORD1 (13 bits) : ^^^^^^ ^^^^^^^
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WORD2 (13 bits) : ^^^^^^^^^^^^^
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WORD3 (13 bits) : ^^^^^^^^^^^^^
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----
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Alternative format (generated using link:https://github.com/luismartingarcia/protocol[protocol^])
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[source]
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----
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./protocol 'Face:3,Data:46,1:1,0:14?bits=32'
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Face| Data |
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+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| |1| 0 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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----
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[source]
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----
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./protocol 'WORD3:13,WORD2:13,WORD1:13,Number:10?bits=32'
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| WORD3 | WORD2 | |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| WORD1 | Number |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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----
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== Encoding
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[%header,cols="2m,5a"]
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@ -199,7 +153,14 @@ func cellIDFromFaceIJ(f, i, j int) CellID {
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----
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[source,rust]
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----
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fn fij_to_cellid(f: u8, s: u32, t: u32) -> u64 {
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const FACE_BITS: u64 = 3;
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const NUM_FACES: u8 = 6;
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const MAX_LEVEL: u64 = 30;
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const POS_BITS: u64 = (2 * MAX_LEVEL) + 1;
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const MAX_SIZE: u64 = 1 << MAX_LEVEL;
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const WRAP_OFFSET: u64 = (NUM_FACES as u64) << POS_BITS;
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fn fij_to_cellid(f: u8, i: u32, j: u32) -> u64 {
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let mut n = u64::from(f) << (POS_BITS - 1);
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let mut bits = u32::from(f & SWAP_MASK);
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