Update docs on how to use a system-provided MPI installation with T8c…

…ode.jl (#1613)

* update docs on how to use a system-provided MPI installation with T8code.jl

* reduce number of characters per line

* adjust path of shared object files

* fix typo

docs/src/parallelization.md

@@ -53,16 +53,24 @@ a system-provided MPI installation with Trixi.jl can be found in the following s
 
 ### [Using a system-provided MPI installation](@id parallel_system_MPI)
 
-When using Trixi.jl with a system-provided MPI backend the underlying [`p4est`](https://github.com/cburstedde/p4est)
-library needs to be compiled with the same MPI installation. Therefore, you also need to use
-a system-provided `p4est` installation (for notes on how to install `p4est` see e.g.
-[here](https://github.com/cburstedde/p4est/blob/master/README), use the configure option
-`--enable-mpi`). In addition, [P4est.jl](https://github.com/trixi-framework/P4est.jl) needs to
-be configured to use the custom `p4est` installation. Follow the steps described
-[here](https://github.com/trixi-framework/P4est.jl/blob/main/README.md) for the configuration.
+When using Trixi.jl with a system-provided MPI backend the underlying
+[`p4est`](https://github.com/cburstedde/p4est) and [`t8code`](https://github.com/DLR-AMR/t8code)
+libraries need to be compiled with the same MPI installation. Therefore, you also need to
+use system-provided `p4est` and `t8code` installations (for notes on how to install `p4est`
+and `t8code` see e.g. [here](https://github.com/cburstedde/p4est/blob/master/README) and
+[here](https://github.com/DLR-AMR/t8code/wiki/Installation), use the configure option
+`--enable-mpi`). Note that `t8code` already comes with a `p4est` installation, so it suffices
+to install `t8code`. In addition, [P4est.jl](https://github.com/trixi-framework/P4est.jl) and
+[T8code.jl](https://github.com/DLR-AMR/T8code.jl) need to be configured to use the custom
+installations. Follow the steps described
+[here](https://github.com/DLR-AMR/T8code.jl/blob/main/README.md#installation) and
+[here](https://github.com/trixi-framework/P4est.jl/blob/main/README.md#installation) for the
+configuration. The paths that point to `libp4est.so` (and potentially to `libsc.so`) need to be
+the same for P4est.jl and T8code.jl. This could e.g. be `libp4est.so` that usually can be found
+in `lib/` or `local/lib/` in the installation directory of `t8code`.
 In total, in your active Julia project you should have a LocalPreferences.toml file with sections
-`[MPIPreferences]` and `[P4est]` as well as an entry `MPIPreferences` in your Project.toml to
-use a custom MPI installation.
+`[MPIPreferences]`, `[T8code]` and `[P4est]` as well as an entry `MPIPreferences` in your
+Project.toml to use a custom MPI installation.
 
 
 ### [Usage](@id parallel_usage)