brief Compilation instructions for Linux, Mac, and Windows

Easiest method is to use provided shell scripts install-dependencies.sh (which installs the required packages/compilers), and setup.sh (which compiles ampsci)
- These might not work on all systems, meaning a manual setup will be required.
You can also compile using the provided Makefile:
Copy "doc/examples/Makefile" from doc/ directory to the working directory
- cp ./doc/examples/Makefile ./
All programs compiled using the Makefile (run make)
The file Makefile has some basic compilation options. It's currently set up to work on most linux systems; you may need to change a few options for others (see below)
Tested with g++ and clang++ on linux and mac

Dependencies / Requirements

c++ compiler that supports c++17
- Tested with clang version 6 and newer; gcc version 7 and newer
- Also tested with Intel [icc 2021.9.0], though this is tested infrequently
LAPACK and BLAS libraries netlib.org/lapack/
GSL (GNU scientific libraries) gnu.org/software/gsl/ [version 2.0 or newer*]
- (it should also work with older versions of GSL, but this is not regularly tested and therefore not guaranteed)
- Updated to work with newer GSL version 2.8; still works with older versions too
[optional] GNU Make (gnu.org/software/make/) - used to compile code
[optional] OpenMP (openmp.org/) - used for parallelisation
[optional] git (git-scm.com/) for version tracking and to keep up-to-date with latest version

Quick-start

This is for ubuntu/linux - for other systems, see below

Get the code from GitHub, using git:
- sudo apt install git
- git clone git@github.com:benroberts999/ampsci.git
- or git clone https://github.com/benroberts999/ampsci.git
Or, direct download (without using git, not recommended):
- https://github.com/benroberts999/ampsci/archive/refs/heads/main.zip
Install dependencies
- sudo apt install g++ liblapack-dev libblas-dev libgsl-dev make libomp-dev
Prepare the Makefile (already setup for ubuntu, you may need minor adjustments, see below)
- cp ./doc/examples/Makefile ./
Compile ampsci using all default options:
- make
Run the first example program
- cp ./doc/examples/ampsci.in ./
- ./ampsci ampsci.in

Compilation: Linux

Instructions for ubuntu; similar commands for other flavours
Install make: sudo apt-get install make
Install GSL libraries: sudo apt-get install libgsl-dev
May also need LAPACK/BLAS libraries: sudo apt-get install libatlas-base-dev liblapack-dev libblas-dev
Install the compiler: sudo apt-get install g++ and/or sudo apt-get install clang++
Then compile by running make from the ampsci directory
To use with openMP (for parallelisation) with clang++, you might have to also install clang openmp libraries: sudo apt install libomp5 (and/or perhaps sudo apt install libomp-dev)

Compilation: MacOS (intel chip)

On mac: use homebrew to install gsl: brew install gsl
homebrew is a package manager; install from https://brew.sh/
Seems to work best with the homebrew version of gcc. Install as: brew install gcc
Note: you may need to change the compiler from g++ to g++-9 (or similar), or update your environment variables, since calling g++ on mac actually calls clang++ by default
You might have to tell the compiler how to link to the GSL library; in Makefile:
- PathForGSL=/usr/local/opt/gnu-scientific-library
Then compile by running make from the ampsci directory
Use openMP for parellelisation when using clang++ on mac:
- If using g++, should work as per normal
- To use openMP with clang, seem to require the llvm version
- brew install llvm
- Then, in the Makefile, set (exact paths may be different for you):
  - CXX=/usr/local/opt/llvm/bin/clang++
  - ExtraInclude=/usr/local/opt/llvm/include/
  - ExtraLink=/usr/local/opt/llvm/lib/
- This seems fragile

Compilation: MacOS (M1/M2/apple silicon chip)

Mostly the same as above, but some of the libraries are installed to different directories by default. In particular:
PathForGSL=/opt/homebrew/Cellar/gsl/2.7

Compilation: Windows

For windows, the easiest way (for me, anyway) is to use the 'windows subsystem for linux' (requires Windows 10+).
Instructions on installation/use here: docs.microsoft.com/en-us/windows/wsl/install.
Then, the compilation + use can proceed as per Linux above.

Common Compilation errors

libgfortran error

Error linking to gfortran/lapack, may be something like this:

ld: .../liblapack.a(xerbla.o): undefined reference to symbol '_gfortran_string_len_trim@GFORTRAN_8' ld: .../libgfortran.so.5: error adding symbols: DSO missing from command line make: *** [build/buildTargets.mk:66: ampsci] Error 1

Sometimes occurs on certain systems (e.g., bunya). In these cases, the fortran libraries need to be linked to explicitely. This can be done by adding -lgfortran to the ExtraFlags option in the Makefile

ExtraFlags=-lgfortran

OpenMP errors

error: unsupported option -fopenmp
error: could not find <omp.h>
openmp (used for parallelisation) is not working. See above for some possible solutions.
Quick fix: change 'UseOpenMP=yes' to 'UseOpenMP=no' in Makefile

GSL Errors

fatal error: gsl/<...>.h: No such file or directory (or similar)
gsl related linking/compilation error:
Could not find required GSL libraries. Either they are not installed, or you need to link to them
1) Ensure GSL is installed (see above for instructions)
2) If GSL library is not installed in _/usr/local/_, you have to tell the compiler where to find the GSL files. Do this by setting the PathForGSL option in Makefile. Common examples:
- PathForGSL=/opt/gsl/2.1/gnu # For UQ's getafix cluster
- PathForGSL=/usr/local/opt/gnu-scientific-library # For my macbook
- Note: the exact path may differ for you, depending on where GSL was installed
error: too few arguments to function ‘int gsl_bspline_deriv_eval
This is because the code is linking to a very old version of GSL. You might need to update GSL. If you have updated GSL (to at least version 2.0) and still get the message, the code is probably linking against the wrong version of GSL; see above to point the compiler to the correct version

ld: Assertion failed: (resultIndex < sectData.atoms.size())

Full error message may look something like:

0x102497648  __assert_rtn + 72
0x1023cbfac  ld::AtomPlacement::findAtom(unsigned char, unsigned long long, ld::AtomPlacement::AtomLoc const*&, long long&) const + 1204
0x1023e1924  ld::InputFiles::SliceParser::parseObjectFile(mach_o::Header const*) const + 15164
0x1023eee30  ld::InputFiles::parseAllFiles(void (ld::AtomFile const*) block_pointer)::$_7::operator()(unsigned long, ld::FileInfo const&) const + 420
0x185a37950  _dispatch_client_callout2 + 20
0x185a4aba0  _dispatch_apply_invoke + 176
0x185a37910  _dispatch_client_callout + 20
0x185a493cc  _dispatch_root_queue_drain + 864
0x185a49a04  _dispatch_worker_thread2 + 156
0x185be10d8  _pthread_wqthread + 228
ld: Assertion failed: (resultIndex < sectData.atoms.size()), function findAtom, file Relocations.cpp, line 1336.
collect2: error: ld returned 1 exit status

This seems to be a bug with M1/M2 mac linker implementation with CommandLineTools version 15.0 (see developer.apple.com/forums/thread/737707)
See also: github.com/Homebrew/homebrew-core/issues/145991
This issue seems to have been resolved in version 15.1 - so run an update if you can.
If you can't update, it seems this can be fixed by adding the following to the Makefile:

LARGS=-Wl,-ld_classic

You shouldn't need to make clean first, but if it doesn't work, try that too.

Others

Sometimes, the compiler will not be able to find the correct libraries (particular, e.g., on clusters). In this case, there are two options in the Makfefile: ExtraInclude and ExtraLink
- These add paths to include the correct directories for both -I "includes" (for compilation), and -L link flags (for linking libraries) in Makefile. These can be a little tricky to get right (don't include the -I or -L)