fortran-使用fortran实现的快速浮点数到字符串转换.zip

# ryu_fortran A Fortran implementation of [Ryu](https://dl.acm.org/doi/10.1145/3296979.3192369) algorithm which converts floating point numbers to decimal strings. It is more effective than internal file approach. This implementation is based on the [Scala](https://github.com/scala-native/scala-native/tree/master/nativelib/src/main/scala/scala/scalanative/runtime/ieee754tostring/ryu) version of Ryu. ## Install ### Fortran package manager Add fpm dependency declaration in the `fpm.toml` file of your project. ```toml [dependencies] ryu_fortran = { git = "https://github.com/St-Maxwell/ryu_fortran" } ``` ## Usage ```fortran use ryu, only: f2shortest, d2shortest, d2fixed, d2exp use iso_fortran_env, only: real32, real64 write (*, "(A)") f2shortest(3.14159_real32) write (*, "(A)") d2shortest(2.718281828_real64) write (*, "(A)") d2fixed(1.2345678987654321_real64, 10) write (*, "(A)") d2exp(299792458._real64, 5) ! 3.14159 ! 2.718281828 ! 1.2345678988 ! 2.99792E+08 ``` ## Test Ryu algorithm is meant to generate the shortest decimal representaion of a floating point number, and is able to preserve the information after conversion. That is, if we convert the produced string back to a floating point number, we should obtain the same binary representation comparing to the original number. `f2shortest`, `d2shortest`, `d2fixed` and `d2exp` have been fully tested using the test cases from [ulfjack/ryu](https://github.com/ulfjack/ryu/tree/master/ryu/tests). To perform the tests, run ```bash fpm test [test-item] ``` where `test-item` can be `test-f2shortest`, `test-d2shortest`, `test-d2fixed` and `test-d2exp`. ## Benchmark * Compiler: gfortran version 9.3.0 (Ubuntu-20.04 WSL2) * Command: `fpm test benchmark --profile release` Results ``` Benchmark for f2shortest f2shortest Time (us): 0.0785894 Std Dev: 0.0118 internal IO Time (us): 0.7998928 Std Dev: 0.0778 Benchmark for d2shortest d2shortest Time (us): 0.1047708 Std Dev: 0.0110 internal IO Time (us): 0.9942683 Std Dev: 0.1660 Benchmark for d2exp d2exp Time (us): 0.1041636 Std Dev: 0.0167 internal IO Time (us): 0.9326320 Std Dev: 0.1252 Benchmark for d2fixed d2fixed Time (us): 0.2314018 Std Dev: 0.2261 internal IO Time (us): 2.3488336 Std Dev: 2.3387 ```