From 2975351a3f5aeb004428aaa112e422432c15aede Mon Sep 17 00:00:00 2001
From: MintoDA1 <51412913+MintoDA1@users.noreply.github.com>
Date: Fri, 28 Jul 2023 11:41:58 -0400
Subject: [PATCH] Finished changes to the README to improve the compiling
 instructions

---
 README.md | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 4ffe2667c..246ff5b9c 100644
--- a/README.md
+++ b/README.md
@@ -69,9 +69,20 @@ You now have a Swiftest repository on your personal machine that you may compile
 
 By far the simplest, most reliable way of compiling the driver program is via a Docker container. The Swiftest project contains a Dockerfile that may be used to generate an executable without needing to provide any external dependencies, other than the Docker engine itself (see [here](https://docs.docker.com/get-docker/) for instructions on obtaining Docker). Once Docker is installed and the Docker engine is running, execute:
 ```
-$ docker build --target=export_driver --output=bin --build-arg MACHINE_CODE_VALUE="Host" [--build-arg EXTRA_CMAKE_OPTIONS=["-D<Additional option you want to pass to CMake>"]
+$ docker build --target=export_driver \
+               --output=bin \
+               --build-arg MACHINE_CODE_VALUE="Host"  \
+             [ --build-arg BUILD_TYPE="*RELEASE*|DEBUG|TESTING|PROFILE" ] \
+             [ --build-arg EXTRA_CMAKE_OPTIONS="-D<Additional option you want to pass to CMake>" ]
 ```
 
+The Docker build will download and compile all of the library dependencies (HDF5, NetCDF-C, and NetCDF-Fortran) as static libraries and the Swiftest driver using Intel compilers. Once completed, the Swiftest executable, called ```swiftest_driver```, should now be created in the ```bin/``` directory. 
+
+> Note: The Dockerfile is designed to build an executable that is compatible with a broad range of CPU architectures by specifying the SSE2 instruction as a target for SIMD instructions using the `-x` compiler option. When compiling on the same CPU archictecture you plan to execute the driver program, for the highest possible SIMD performance, use `--build-arg MACHINE_CODE_VALUE="Host" to override the default `MACHINE_CODE_VALUE="SSE2"`. For additional options see [here](https://www.intel.com/content/www/us/en/docs/fortran-compiler/developer-guide-reference/2023-1/x-qx.html).
+
+The optional Docker argument `EXTRA_CMAKE_OPTIONS` is provided to pass any additional CMake arguments (see below).
+
+
 ***Compiling `swiftest_driver` using CMake***
 
 The Swiftest driver program is written in modern Fortran and must be compiled before it can be run. After compilation, an executable, called the `swiftest_driver``, will have been created in the ```bin/``` directory. 
@@ -120,7 +131,6 @@ $ cmake -B build -S . -LA
 The Swiftest executable, called ```swiftest_driver```, should now be created in the ```bin/``` directory.
 
 
-
 **Download the `swiftest_driver` as a Docker or Singularity container.**
 
 The Swiftest driver is available as a Docker container on DockerHub in two versions: Intel and GNU. The Intel version was compiled for the x86_64 CPU using the Intel classic Fortran compiler. The GNU version was compliled for the x86_64 CPU using gfortran. The Intel version is faster than the GNU version (though not as fast as a native compile to the target CPU that you wish to run it on due to vectorization optimizations that Swiftest takes advantage of), however it is much larger: The Intel version is ~2.7GB while the GNU version is ~300MB. The Singularity container pulls from the same DockerHub container.