-
Notifications
You must be signed in to change notification settings - Fork 86
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
use std::uint32_t, move ConfigSet to core, and del throw in constexpr
delete throw in constexpr because it fails in gcc <= 5.x Co-authored-by: Aditya Kashi <aditya.kashi@kit.edu> Co-authored-by: Terry Cojean <terry.cojean@kit.edu> Co-authored-by: Tobias Ribizel <ribizel@kit.edu>
- Loading branch information
4 people
committed
May 28, 2021
1 parent
6ab97cd
commit 7f72418
Showing
6 changed files
with
270 additions
and
243 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,209 @@ | ||
| /*******************************<GINKGO LICENSE>****************************** | ||
| Copyright (c) 2017-2021, the Ginkgo authors | ||
| All rights reserved. | ||
| Redistribution and use in source and binary forms, with or without | ||
| modification, are permitted provided that the following conditions | ||
| are met: | ||
| 1. Redistributions of source code must retain the above copyright | ||
| notice, this list of conditions and the following disclaimer. | ||
| 2. Redistributions in binary form must reproduce the above copyright | ||
| notice, this list of conditions and the following disclaimer in the | ||
| documentation and/or other materials provided with the distribution. | ||
| 3. Neither the name of the copyright holder nor the names of its | ||
| contributors may be used to endorse or promote products derived from | ||
| this software without specific prior written permission. | ||
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS | ||
| IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED | ||
| TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A | ||
| PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | ||
| HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | ||
| SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | ||
| LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | ||
| DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | ||
| THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | ||
| (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | ||
| OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | ||
| ******************************<GINKGO LICENSE>*******************************/ | ||
|
|
||
| #ifndef GKO_CORE_BASE_TYPES_HPP_ | ||
| #define GKO_CORE_BASE_TYPES_HPP_ | ||
|
|
||
|
|
||
| #include <array> | ||
| #include <cstdint> | ||
| #include <type_traits> | ||
|
|
||
|
|
||
| namespace gko { | ||
| namespace detail { | ||
|
|
||
|
|
||
| /** | ||
| * mask gives the integer with Size activated bits in the end | ||
| * | ||
| * @tparam Size the number of activated bits | ||
| * @tparam ValueType the type of mask, which uses std::uint32_t as default | ||
| * | ||
| * @return the ValueType with Size activated bits in the end | ||
| */ | ||
| template <int Size, typename ValueType = std::uint32_t> | ||
| constexpr std::enable_if_t<(Size < sizeof(ValueType) * 8), ValueType> mask() | ||
| { | ||
| return (ValueType{1} << Size) - 1; | ||
| } | ||
|
|
||
| /** | ||
| * @copydoc mask() | ||
| * | ||
| * @note this is special case for the Size = the number of bits of ValueType | ||
| */ | ||
| template <int Size, typename ValueType = std::uint32_t> | ||
| constexpr std::enable_if_t<Size == sizeof(ValueType) * 8, ValueType> mask() | ||
| { | ||
| return ~ValueType{}; | ||
| } | ||
|
|
||
|
|
||
| /** | ||
| * shift calculates the number of bits for shifting | ||
| * | ||
| * @tparam current_shift the current position of shifting | ||
| * @tparam num_groups the number of elements in array | ||
| * | ||
| * @return the number of shifting bits | ||
| * | ||
| * @note this is the last case of nested template | ||
| */ | ||
| template <int current_shift, int num_groups> | ||
| constexpr std::enable_if_t<(num_groups == current_shift + 1), int> shift( | ||
| const std::array<unsigned char, num_groups> &bits) | ||
| { | ||
| return 0; | ||
| } | ||
|
|
||
| /** | ||
| * @copydoc shift(const std::array<char, num_groups>) | ||
| * | ||
| * @note this is the usual case of nested template | ||
| */ | ||
| template <int current_shift, int num_groups> | ||
| constexpr std::enable_if_t<(num_groups > current_shift + 1), int> shift( | ||
| const std::array<unsigned char, num_groups> &bits) | ||
| { | ||
| return bits[current_shift + 1] + | ||
| shift<(current_shift + 1), num_groups>(bits); | ||
| } | ||
|
|
||
|
|
||
| } // namespace detail | ||
|
|
||
|
|
||
| /** | ||
| * ConfigSet is a way to embed several information into one integer by given | ||
| * certain bits. | ||
| * | ||
| * The usage will be the following | ||
| * Set the method with bits Cfg = ConfigSet<b_0, b_1, ..., b_k> | ||
| * Encode the given infomation encoded = Cfg::encode(x_0, x_1, ..., x_k) | ||
| * Decode the specific position information x_t = Cfg::decode<t>(encoded) | ||
| * The encoded result will use 32 bits to record | ||
| * rrrrr0..01....1...k..k, which 1/2/.../k means the bits store the information | ||
| * for 1/2/.../k position and r is for rest of unused bits. | ||
| * | ||
| * Denote $B_t = \sum_{i = t+1}^k b_i$ and $F(X) = Cfg::encode(x_0, ..., x_k)$. | ||
| * Have $F(X) = \sum_{i = 0}^k (x_i << B_i) = \sum_{i = 0}^k (x_i * 2^{B_i})$. | ||
| * For all i, we have $0 <= x_i < 2^{b_i}$. | ||
| * $x_i$, $2^{B_i}$ are non-negative, so | ||
| * $F(X) = 0$ <=> $X = \{0\}$, $x_i = 0$ for all i. | ||
| * Assume $F(X) = F(Y)$, then | ||
| * $0 = |F(X) - F(Y)| = |F(X-Y)| = F(|X - Y|)$. | ||
| * $|x_i - y_i|$ is still in the same range $0 <= |x_i - y_i| < 2^{b_i}$. | ||
| * Thus, $F(|X - Y|) = 0$ -> $|X - Y| = \{0\}$, $x_i - y_i = 0$ -> $X = Y$. | ||
| * F is one-to-one function if $0 <= x_i < 2^{b_i}$ for all i. | ||
| * For any encoded result R, we can use the following to get the decoded series. | ||
| * for i = k to 0; | ||
| * $x_i = R % b_i$; | ||
| * $R = R / bi$; | ||
| * endfor; | ||
| * For any R in the range $[0, 2^{B_0})$, we have X such that $F(X) = R$. | ||
| * F is onto function. | ||
| * Thus, F is bijection. | ||
| * | ||
| * @tparam num_bits... the number of bits for each position. | ||
| * | ||
| * @note the num_bit is required at least $ceil(log_2(maxval) + 1)$ | ||
| */ | ||
| template <unsigned char... num_bits> | ||
| class ConfigSet { | ||
| public: | ||
| static constexpr unsigned num_groups = sizeof...(num_bits); | ||
| static constexpr std::array<unsigned char, num_groups> bits{num_bits...}; | ||
|
|
||
| /** | ||
| * Decodes the `position` information from encoded | ||
| * | ||
| * @tparam position the position of desired information | ||
| * | ||
| * @param encoded the encoded integer | ||
| * | ||
| * @return the decoded information at position | ||
| */ | ||
| template <int position> | ||
| static constexpr std::uint32_t decode(std::uint32_t encoded) | ||
| { | ||
| static_assert(position < num_groups, | ||
| "This position is over the bounds."); | ||
| constexpr int shift = detail::shift<position, num_groups>(bits); | ||
| constexpr auto mask = detail::mask<bits[position]>(); | ||
| return (encoded >> shift) & mask; | ||
| } | ||
|
|
||
| /** | ||
| * Encodes the information with given bit set to encoded integer. | ||
| * | ||
| * @note the last case of nested template. | ||
| */ | ||
| template <unsigned current_iter> | ||
| static constexpr std::enable_if_t<(current_iter == num_groups), | ||
| std::uint32_t> | ||
| encode() | ||
| { | ||
| return 0; | ||
| } | ||
|
|
||
| /** | ||
| * Encodes the information with given bit set to encoded integer. | ||
| * | ||
| * @tparam current_iter the encoded place | ||
| * @tparam Rest... the rest type | ||
| * | ||
| * @param first the current encoded information | ||
| * @param rest... the rest of other information waiting for encoding | ||
| * | ||
| * @return the encoded integer | ||
| */ | ||
| template <unsigned current_iter = 0, typename... Rest> | ||
| static constexpr std::enable_if_t<(current_iter < num_groups), | ||
| std::uint32_t> | ||
| encode(std::uint32_t first, Rest &&... rest) | ||
| { | ||
| constexpr int shift = detail::shift<current_iter, num_groups>(bits); | ||
| if (current_iter == 0) { | ||
| static_assert( | ||
| bits[current_iter] + shift <= sizeof(std::uint32_t) * 8, | ||
| "the total bits usage is larger than std::uint32_t bits"); | ||
| } | ||
| return (first << shift) | | ||
| encode<current_iter + 1>(std::forward<Rest>(rest)...); | ||
| } | ||
| }; | ||
|
|
||
|
|
||
| } // namespace gko | ||
|
|
||
| #endif // GKO_CORE_BASE_TYPES_HPP_ |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.