diff options
Diffstat (limited to 'src/Bitmap_cubical_complex/include/gudhi/phat/representations/bit_tree_pivot_column.h')
| -rw-r--r-- | src/Bitmap_cubical_complex/include/gudhi/phat/representations/bit_tree_pivot_column.h | 169 |
1 files changed, 0 insertions, 169 deletions
diff --git a/src/Bitmap_cubical_complex/include/gudhi/phat/representations/bit_tree_pivot_column.h b/src/Bitmap_cubical_complex/include/gudhi/phat/representations/bit_tree_pivot_column.h deleted file mode 100644 index 34366d6a..00000000 --- a/src/Bitmap_cubical_complex/include/gudhi/phat/representations/bit_tree_pivot_column.h +++ /dev/null @@ -1,169 +0,0 @@ -/* Copyright 2013 IST Austria
- Contributed by: Hubert Wagner
-
- This file is part of PHAT.
-
- PHAT 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.
-
- PHAT 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 PHAT. If not, see <http://www.gnu.org/licenses/>. */
-
-#pragma once
-
-#include "../helpers/misc.h"
-#include "../representations/abstract_pivot_column.h"
-
-namespace phat {
-
- // This is a bitset indexed with a 64-ary tree. Each node in the index
- // has 64 bits; i-th bit says that the i-th subtree is non-empty.
- // Supports practically O(1), inplace, zero-allocation: insert, remove, max_element
- // and clear in O(number of ones in the bitset).
- // 'add_index' is still the real bottleneck in practice.
- class bit_tree_column
- {
- size_t offset; // data[i + offset] = ith block of the data-bitset
- typedef uint64_t block_type;
- std::vector< block_type > data;
-
- // this static is not a problem with OMP, it's initialized just after program starts
- static const size_t debrujin_magic_table[64];
-
- enum { block_size_in_bits = 64 };
- enum { block_shift = 6 };
-
- // Some magic: http://graphics.stanford.edu/~seander/bithacks.html
- // Gets the position of the rightmost bit of 'x'. 0 means the most significant bit.
- // (-x)&x isolates the rightmost bit.
- // The whole method is much faster than calling log2i, and very comparable to using ScanBitForward/Reverse intrinsic,
- // which should be one CPU instruction, but is not portable.
- size_t rightmost_pos(const block_type value) const
- {
- return 64 - 1 - debrujin_magic_table[((value & (-(int64_t)value))*0x07EDD5E59A4E28C2) >> 58];
- }
-
- public:
-
- void init(index num_cols)
- {
- int64_t n = 1; // in case of overflow
- int64_t bottom_blocks_needed = (num_cols+block_size_in_bits-1)/block_size_in_bits;
- int64_t upper_blocks = 1;
-
- // How many blocks/nodes of index needed to index the whole bitset?
- while(n * block_size_in_bits < bottom_blocks_needed)
- {
- n *= block_size_in_bits;
- upper_blocks += n;
- }
-
- offset = upper_blocks;
- data.resize(upper_blocks + bottom_blocks_needed, 0);
- }
-
- index max_index() const
- {
- if (!data[0])
- return -1;
-
- const size_t size = data.size();
- size_t n = 0;
-
- while(true)
- {
- const block_type val = data[n];
- const size_t index = rightmost_pos(val);
- const size_t newn = (n << block_shift) + index + 1;
-
- if (newn >= size)
- {
- const size_t bottom_index = n - offset;
- return (bottom_index << block_shift) + index;
- }
-
- n = newn;
- }
-
- return -1;
- }
-
- bool empty() const
- {
- return data[0] == 0;
- }
-
- void add_index(const size_t entry)
- {
- const block_type ONE = 1;
- const block_type block_modulo_mask = ((ONE << block_shift) - 1);
- size_t index_in_level = entry >> block_shift;
- size_t address = index_in_level + offset;
- size_t index_in_block = entry & block_modulo_mask;
-
- block_type mask = (ONE << (block_size_in_bits - index_in_block - 1));
-
- while(true)
- {
- data[address]^=mask;
-
- // First we check if we reached the root.
- // Also, if anyone else was in this block, we don't need to update the path up.
- if (!address || (data[address] & ~mask))
- return;
-
- index_in_block = index_in_level & block_modulo_mask;
- index_in_level >>= block_shift;
- --address;
- address >>= block_shift;
- mask = (ONE << (block_size_in_bits - index_in_block - 1));
- }
- }
-
- void get_column_and_clear(column &out)
- {
- out.clear();
- while(true)
- {
- index mx = this->max_index();
- if (mx == -1)
- break;
- out.push_back(mx);
- add_index(mx);
- }
-
- std::reverse(out.begin(), out.end());
- }
-
- void add_column(const column &col)
- {
- for (size_t i = 0; i < col.size(); ++i)
- {
- add_index(col[i]);
- }
- }
-
- bool empty() {
- return !data[0];
- }
- };
-
- const size_t bit_tree_column::debrujin_magic_table[64] = {
- 63, 0, 58, 1, 59, 47, 53, 2,
- 60, 39, 48, 27, 54, 33, 42, 3,
- 61, 51, 37, 40, 49, 18, 28, 20,
- 55, 30, 34, 11, 43, 14, 22, 4,
- 62, 57, 46, 52, 38, 26, 32, 41,
- 50, 36, 17, 19, 29, 10, 13, 21,
- 56, 45, 25, 31, 35, 16, 9, 12,
- 44, 24, 15, 8, 23, 7, 6, 5};
-
- typedef abstract_pivot_column<bit_tree_column> bit_tree_pivot_column;
-}
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