Release 1.10.0 #187
Merged
Release 1.10.0 #187
Conversation
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
Its definition was broken for non-Clang non-GCC compilers.
Add some basic tests to ensure that every public-facing header can be included without triggering any error.
That feature used to only be available in C++17, when the conversion of lambdas to function pointers was made constepxr. The new design doesn't use lambdas anymore, which allows the conversion to always be constexpr. This commit also simplifies the implementation, making it less redundant and easier to extend. Not using lambdas also means easier to understand error messages and less potential generic lambda bloat.
Using signed integers ensures that we won't accidentally generate big positive numbers instead of negative ones (which was most likely the case for the alternating distributions).
While everything else compiles fine, the conversion from a sorter to a function pointer seems broken with MSVC. It is reasonable to have this single feature not working.
Grailsort creates invalid pointers here and there that are never dereferenced, so generally don't cause any issues. However, forming invalid iterators like that might cause issues, and MSVC debug iterators do trip on grailsort. This commit only fixes "strategy 3": when the algorithm can't find at least 4 unique keys in the collection.
MSVC support
Add the measure of presortedness SUS(X) first described in Sorting Shuffled Monotone Sequences by Levcopoulos and Petersson. SUS(X) is the minimum number of non-decreasing subsequences (of possibly non adjacent elements) into which X can be partitioned. It happens to be equal to the size of the longest decreasing subsequence of X minus 1, which is why we reuse the algorithm used to compute Rem(X) to compute it.
Introduce rvalue_type_t which is rvalue_reference_t stripped of its constness and referenceness, and use it everywhere it's relevant.
Instead of performing a binary search on the encroaching list that checks both the greatest and smallest element, compare first to the head and tail of the last encroaching list, then decide whether to binary search the heads, binary search the tails, or create a new list where to add the element. This optimization was actually described in the original paper, but I failed to understand it until recently. It is possible because the last list has the biggest of the heads (smaller elements), and the smallest of the tails (bigger elements). At worst the number of comparisons is the same as with the previous algorithm, at best it performs up to 20% fewer comparisons. I haven't noticed a big difference when sorting arithmetic types, but it should make a noticeable difference for types with a more expensive comparisons.
This is basically the optimization that was implemented in melsort a few commits ago: it compares every new element to the head and tail of the last encroaching list first, then decides whether to perform a binary search over the heads or the tails of the encroaching lists. This optimization leads to up to 40% fewer comparisons performed in some cases.
This will allow future algorithms to use different but compatible node types as needed. The node pool was changed in a similar way: at some point it is just a pool of nodes that share some properties, allowing more types of nodes is good. fixed_size_list_node was renamed to list_node because it could very well be used in non-fixed-size lists in the future.
Implements the slabsort algorithm described by C. Levcopoulos and O. Petersson in Sorting Shuffled Monotone Sequences. Despite its suspiciously simple-looking 7 lines of pseudocode, this algorithm required non-trivial changes in fixed_size_list and a small refactoring of melsort, as weel as the addition of stable_partition to the library details.
Be it in benchmarks or in tests, I never notived a significant difference between the distributions shuffled_16_values and alternating_16_values. The latter revealed pretty useless at the end of the day, so I'm removing it.
This a stream from upstream, which also simplifies the block partition logic.
I'm not sure how this managed to slip under my radar since 2015, that's a bit embarrassing.
JFrog is sunsetting Bintray, so there's no use publishing more packages there or mentioning them in the documentation. I don't expect this to cause issues among users.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
No description provided.