powersort/README.md
2025-01-01 18:00:44 +00:00

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# Bring Powersort to Java
Implementation of Powersort with the aim of integrating it into OpenJDK. Benchmarks are used to ensure that the runtime of the new sorting algorithm is never slower than the current Timsort implementation.
<!-- TOC -->
* [Bring Powersort to Java](#bring-powersort-to-java)
* [Setup](#setup)
* [Development Setup with nix](#development-setup-with-nix)
* [Tasks](#tasks)
* [Test Cases](#test-cases)
* [Benchmark](#benchmark)
<!-- TOC -->
## Setup
We use Gradle for dependency and build management.
**Commandline**
Check which Java toolchains Gradle finds:
```shell
./gradlew javaToolchains
```
This should include version >= 23, e.g.:
```
+ N/A JDK 23-ga
| Location: /nix/store/48290hnlb13xmwjw9y16a1s785993bv7-openjdk-23-ga/lib/openjdk
| Language Version: 23
| Vendor: N/A
| Architecture: amd64
| Is JDK: true
| Detected by: Current JVM
```
### Development Setup with nix
The provided [shell.nix](shell.nix) file can be used to set up a development environment with IntelliJ. The only prerequisite is to have a working `nix` installation for which there are multiple possibilities, e.g:
```shell
# https://github.com/DeterminateSystems/nix-installer?tab=readme-ov-file#determinate-nix-installer
curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | \
sh -s -- install
```
Then the dependencies (JDK23, Gradle, IntelliJ) can be installed with:
```shell
nix-shell
```
**IntelliJ**
When using `nix-shell`, some manual configuration is necessary:
- `STRG` `ALT` `SHIFT` `s` -> SDK -> add JDK ->
- home path: `/usr/lib/openjdk`
- name: `usr-lib-jdk`
- `STRG` `ALT` `s` -> build tools -> gradle ->
- local installation: `/usr/lib/gradle`
- Gradle JVM: `usr-lib-jdk`
## Tasks
List all Gradle tasks which can be run:
```shell
./gradlew tasks
```
This can also be done graphically in IntelliJ:
![intellij-gradle.png](intellij-gradle.png)
## Test Cases
Run the task "test":
```shell
./gradlew test
```
## Benchmark
There are two different benchmarks. One is based on the JMH benchmark framework, the other one is a custom benchmark implementation.
```shell
./gradlew jmh
./gradlew runCustomBenchmark
```