dragonbox
C++ Format
dragonbox | C++ Format | |
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9 | 161 | |
498 | 19,350 | |
- | 1.0% | |
9.0 | 9.7 | |
5 days ago | 4 days ago | |
C++ | C++ | |
Apache License 2.0 | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
dragonbox
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23 years into my career, I still love PHP and JavaScript
Apparently exact minimal float-to-string conversion is more recent than I thought, and many languages used to print more (Python?) or less (PHP) decimal digits than necessary to uniquely identify the bit pattern. Python correctly prints 46000.80 + 553.04 as 46553.840000000004, but I don't know if it ever prints more digits than needed. One recent algorithm for printing floats exactly is https://github.com/ulfjack/ryu, though I'm unaware what's the state-of-the-art (https://github.com/jk-jeon/dragonbox claims to be a benchmark and the best algorithm).
- Dragonbox: Fast Float-to-String Conversion
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C++ I wrote a simple and fast formatting library for strings
A recent update to fmt was posted to r/cpp 3 days ago (https://www.reddit.com/r/cpp/comments/vrxkt0/fmt_90_released_with_improvements_to_floating/), and since that's still fresh on people's minds, they'll wonder how yours compares; and they'll probably wonder how it compares in terms of precision, round trip-ability, and performance of DragonBox https://github.com/jk-jeon/dragonbox. By "they", I probably mean "me" :D.
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I created something much faster than a std::string
Existing fast and correct float-to-string implementations are out there. Just use them: https://github.com/jk-jeon/dragonbox. Or maybe use your stdlib if it has good support
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How to read ascii files faster?
Parse floats faster with dragonbox
- Dragonbox 1.1.0 is released (a fast float-to-string conversion algorithm)
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C++20 std::format is already std::regex 2.0 situation.
Even if what you say is true, it makes little sense to not reuse it. There are other concerns here and one of them is code size. But to address the performance issue, fmtlib is doing under 50ns for most fp numbers via dragonbox(https://github.com/jk-jeon/dragonbox has the chart). So still cpu bound, but all FP output is CPU bound. At this point, what prices are we trading for faster?
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First release of dragonbox, a fast float-to-string conversion algorithm, is available
There are some benchmarks in https://github.com/jk-jeon/dragonbox#performance. TL;DR it's faster than other state of the art algorithms like Ryu, Schubfach and variations of Grisu. We saw a nice speed up when switching from Grisu3 to Dragonbox in {fmt}: https://github.com/fmtlib/fmt/pull/1882 and it has been improved even more since then.
C++ Format
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C++ left arrow operator (2016)
Continuation passing monads form the basis of a perfectly valid and usable software architecture and programming pattern.
In the case of ostream and operator<<, this pattern reduces the number of intermediate objects that would otherwise be constructed.
If you object to iostream on religious or stylistic grounds, there's always fmt which is more like Go or Python string interpolation.[0]
0. https://fmt.dev
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C++ Game Utility Libraries: for Game Dev Rustaceans
GitHub repo: fmtlib/fmt
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Creating k-NN with C++ (from Scratch)
cmake_minimum_required(VERSION 3.5) project(knn_cpp CXX) # Set up C++ version and properties include(CheckIncludeFileCXX) check_include_file_cxx(any HAS_ANY) check_include_file_cxx(string_view HAS_STRING_VIEW) check_include_file_cxx(coroutine HAS_COROUTINE) set(CMAKE_CXX_STANDARD 20) set(CMAKE_BUILD_TYPE Debug) set(CMAKE_CXX_STANDARD_REQUIRED ON) set(CMAKE_CXX_EXTENSIONS OFF) # Copy data file to build directory file(COPY ${CMAKE_CURRENT_SOURCE_DIR}/iris.data DESTINATION ${CMAKE_CURRENT_BINARY_DIR}) # Download library usinng FetchContent include(FetchContent) FetchContent_Declare(matplotplusplus GIT_REPOSITORY https://github.com/alandefreitas/matplotplusplus GIT_TAG origin/master) FetchContent_GetProperties(matplotplusplus) if(NOT matplotplusplus_POPULATED) FetchContent_Populate(matplotplusplus) add_subdirectory(${matplotplusplus_SOURCE_DIR} ${matplotplusplus_BINARY_DIR} EXCLUDE_FROM_ALL) endif() FetchContent_Declare( fmt GIT_REPOSITORY https://github.com/fmtlib/fmt.git GIT_TAG 7.1.3 # Adjust the version as needed ) FetchContent_MakeAvailable(fmt) # Add executable and link project libraries and folders add_executable(${PROJECT_NAME} main.cc) target_link_libraries(${PROJECT_NAME} PUBLIC matplot fmt::fmt) aux_source_directory(lib LIB_SRC) target_include_directories(${PROJECT_NAME} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}) target_sources(${PROJECT_NAME} PRIVATE ${LIB_SRC}) add_subdirectory(tests)
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Optimizing the unoptimizable: a journey to faster C++ compile times
Good catch, thanks! Fixed now. This explains why the difference was kinda low compared to another benchmark: https://github.com/fmtlib/fmt?tab=readme-ov-file#compile-tim....
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Learn Modern C++
> This is from C++23, right?
std::println is, yes.
> I wonder how available this is within compilers
https://en.cppreference.com/w/cpp/compiler_support says clang, gcc, and msvc all support it, though I don't know how recent those versions are off the top of my head.
In my understanding, with this specific feature, if you want a polyfill for older compilers, or to use some more cutting-edge features that haven't been standardized yet, https://github.com/fmtlib/fmt is available to you.
- The C++20 Naughty and Nice List for Game Devs
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For processing strings, streams in C++ can be slow
{fmt} has internal buffering but it's not yet exposed to users. There is a feature request for it: https://github.com/fmtlib/fmt/issues/2354. FILE buffering is not too bad but it can be easily optimized: https://www.zverovich.net/2020/08/04/optimal-file-buffer-siz....
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adoption of fmt based logging
Automatic use of operator<< when that exists was present in fmt until version 9.0.0. In version 9 you could use FMT_DEPRECATED_OSTREAM to opt in the old behaviour, but this too was removed in version 10.0.0. Now there is no way to automatically use operator<<.
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What's your favorite c++20 feature that should've been there 10 years ago?
You can install it https://github.com/fmtlib/fmt
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Codebases to read
Additionally, if you like low level stuff, check out libfmt (https://github.com/fmtlib/fmt) - not a big project, not difficult to understand. Or something like simdjson (https://github.com/simdjson/simdjson).
What are some alternatives?
fast_float - Fast and exact implementation of the C++ from_chars functions for number types: 4x to 10x faster than strtod, part of GCC 12 and WebKit/Safari
spdlog - Fast C++ logging library.
ryu - Converts floating point numbers to decimal strings
Better Enums - C++ compile-time enum to string, iteration, in a single header file
ryu - Ryu component-based software defined networking framework
ZXing - ZXing ("Zebra Crossing") barcode scanning library for Java, Android
dtoa-benchmark - C++ double-to-string conversion benchmark
FastFormat - The fastest, most robust C++ formatting library
itoa - Fast integer to ascii / integer to string conversion
ZBar - Clone of the mercurial repository http://zbar.hg.sourceforge.net:8000/hgroot/zbar/zbar
cpp-xstring - A system to handle strings easier and faster
Scintilla