Add some installation instructions

README.md

@@ -34,3 +34,42 @@ Prerequisits: Java 8+ SDK, `git`
 4. Download IDEA IntelliJ (http://www.jetbrains.com/idea/) and choose to install the Scala Plugin during setup.
 5. Launch IntelliJ. From the menu choose `File` -> `Open...`. Then, select `$SHINE_ROOT` and press `OK`.
 6. From the menu bar choose `Run` -> `Edit Configurations...`. Under `Templates` choose `ScalaTest` and add the following line to `VM parameters`: `-Djava.library.path=lib/executor/lib/Executor/build -Xss26m` (this will tell IntelliJ where to find the Executor library and use 26MB of thread stack size which is needed for arithmetic simplifactions sometimes).
+
+#### Dependencies and linking to OpenCL
+
+##### On NixOS:
+
+1. Add `pkgs.intel-ocl` to `hardware.opengl.extraPackages` and `nixos-rebuild`.
+   Running `nix-shell -p clinfo --run clinfo` should show OpenCL support.
+2. You will need `sbt`, `cmake` and `gcc` to compile the project: `nix-env -iA nixos.sbt nixos.cmake nixos.gcc`.
+3. You will need `clang` to run some of the tests, however some utilities clash with `gcc`s, so we need to:
+   ```
+   nix-env --set-flag priority 15 gcc-wrapper # give gcc less priority
+   nix-env -iA nixos.clang                    # install clang
+   ```
+4. Help `FindOpenCL` find the OpenCL library in NixOS:
+   ```
+   export LD_LIBRARY_PATH="${nix-build '<nixos>' --no-build-output ocl-icd}/lib/:$LD_LIBRARY_PATH"
+   sbt compile
+   ```
+   (From now on `sbt compile` does not need to be told where the OpenCL bindings are.)
+5. We can now run the tests with `sbt test`.
+
+##### On Debian:
+
+1. Install Portable OpenCL: `apt-get install pocl`
+2. Install the build dependencies:
+   ```
+   apt-get install cmake software-properties-common g++ clang-7 libxtst6 libxrender1 libxext6
+   ln -s /usr/bin/clang-7 /usr/bin/clang
+   ln -s /usr/bin/clang-cpp-7 /usr/bin/clang++
+   ```
+3. Compile with `sbt compile` and test with `sbt test`.
+
+
+##### As a Docker image
+
+You can find the build file for a Docker image here:
+https://github.com/michel-steuwer/docker-scala-opencl
+
+Note that AMD's SDK is stored with git lfs, so you will have to download it after checking out the repository.