Merge pull request #119 from nauaneed/master2main

doc: omp install on macos

Author: prabhuramachandran

docs/source/installation.rst

@@ -110,15 +110,27 @@ OpenMP on MacOS
 These instructions are a bit old and only if you are not using conda as
 discussed above.
 
-The default clang compiler available on MacOS uses an LLVM backend and does
+│The default clang compiler available on MacOS uses an LLVM backend and does
 not support OpenMP_ out of the box. There are two ways to support OpenMP. The
 first involves installing the OpenMP support for clang. This can be done with
 brew_ using::
 
   $ brew install libomp
 
-Once that is done, it should "just work". If you get strange errors, try
-setting the ``MACOSX_DEPLOYMENT_TARGET`` as shown in the previous section.
+`LLVM <https://formulae.brew.sh/formula/llvm>`_ can also be installed using
+brew_, likewise. Once this is done, you
+can use the following config_::
+
+    import os
+    os.environ['CC'] = '/opt/homebrew/opt/llvm@15/bin/clang'
+    os.environ['CXX'] = '/opt/homebrew/opt/llvm@15/bin/clang++'
+    OMP_CFLAGS=['-I/opt/homebrew/opt/libomp/include', '-I/opt/homebrew/opt/llvm@15/include', '-Xclang', '-fopenmp']
+    OMP_LINK=['-L/opt/homebrew/opt/libomp/lib', '-L/opt/homebrew/opt/llvm@15/lib', '-lomp']
+
+The above config assumes that you have installed `llvm@15`. You can change the
+config according to the version at the time of installing. Once that is done,
+it should "just work". If you get strange errors, you can also try
+setting the ``MACOSX_DEPLOYMENT_TARGET``  as shown in the previous section.
 
 Another option is to install GCC for MacOS available on brew_ using ::