edits for issue 530

doc.zih.tu-dresden.de/docs/software/compilers.md

@@ -67,19 +67,29 @@ Different architectures of CPUs feature different vector extensions (like SSE4.2
 to accelerate computations.
 The following matrix shows proper compiler flags for the architectures at the ZIH:
 
-| HPC System | Architecture       | GCC                  | Intel                | PGI |
+| HPC System | Architecture       | GCC                  | Intel                | Nvidia HPC |
 |------------|--------------------|----------------------|----------------------|-----|
-| [`Alpha Centauri`](../jobs_and_resources/alpha_centauri.md) | AMD Rome            | `-march=znver2`      | `-march=core-avx2`   | `-tp=zen`     |
-| [`Barnard`](../jobs_and_resources/barnard.md)      | AMD Sapphire Rapids | `-march=znver2`      | `-march=core-avx2`   | `-tp=zen`     |
-| [`Julia`](../jobs_and_resources/julia.md)          | Intel Cascade Lake  | `-march=cascadelake` | `-march=cascadelake` | `-tp=skylake` |
-| [`Power9`](../jobs_and_resources/power9.md)        | IBM Power9          | `-march=znver2`      | `-march=core-avx2`   | `-tp=zen`     |
-| [`Romeo`](../jobs_and_resources/romeo.md)          | AMD Rome            | `-march=znver2`      | `-march=core-avx2`   | `-tp=zen`     |
-| All                                                | Host's architecture | `-march=native`      | `-xHost`             |               |
-
-To build an executable for different node types (e.g. Cascade Lake with AVX512 and
-Haswell without AVX512) the option `-march=haswell -axcascadelake` (for Intel compilers)
-uses vector extension up to AVX2 as default path and runs along a different execution
-path if AVX512 is available.
+| [`Alpha Centauri`](../jobs_and_resources/alpha_centauri.md) | AMD Rome   | `-march=znver2`      | `-march=core-avx2`   | `-tp=zen2`               |
+| [`Barnard`](../jobs_and_resources/barnard.md)      | AMD Sapphire Rapids | `-march=sapphirerapids`      | `-march=core-sapphirerapids`   |      |
+| [`Julia`](../jobs_and_resources/julia.md)          | Intel Cascade Lake  | `-march=cascadelake` | `-march=cascadelake` | `-tp=cascadelake`        |
+| [`Romeo`](../jobs_and_resources/romeo.md)          | AMD Rome            | `-march=znver2`      | `-march=core-avx2`   | `-tp=zen2`               |
+| All x86                                               | Host's architecture | `-march=native`      | `-xHost` or `-march=native` |  `-tp=host`    |
+| [`Power9`](../jobs_and_resources/power9.md)        | IBM Power9          | `-mcpu=power9` or `-mcpu=native`          | | `-tp=pwr9` or `-tp=host` |
+
+
+To build an executable for different node types with the Intel compiler, use
+`-axcode`, where `code` is to be replaced with one or more target architectures.
+For Cascade Lake and Sapphire Rapids. the option `-axcascadelake,sapphirerapids`
+(for Intel compilers) instructs the compiler to optimized code paths for the
+specified architecture(s), if possible.
+If the application is executed on one of these architectures, the optimized code
+path will be chosen.
+A baseline code path will also be generated.
+This path is used on other architectures than the specified ones and is used
+in code sections that were not optimized by the compiler for a specific architecture.
+Other optimization flags can be used as well for, e.g. `-O3`.
+However, the `-march` option cannot be used here, as this will overwrite the
+`-axcode` option.
 This increases the size of the program code (might result in
 poorer L1 instruction cache hits) but enables to run the same program on
-different hardware types.
+different hardware types with compiler optimizations.