QuantumEspresso

[Sezoir]

Enable building and execution of the QuantumEspresso application with the LLVM Flang compiler.

[Sezoir]

Next steps: I am not planning to take on this project. This is just an initial report found. Please feel free to work on this.

Quantum ESPRESSO:

https://gitlab.com/QEF/q-e

The build system for Quantum Espresso can be built with either CMake, or using there custom configure script. Since CMake does not currently support flang-new, I'll focus on using the custom configure script in this report.

Initial report for Quantum ESPRESSO:

At the time of writing there seems to be conflicting information between the online documentation (Section 2.7.1 states "Fortran and C compilers, compliant with F2003 and C89 standards") and the repository documentation (Doc/user_guide.tex which states "you need a Fortran compiler compliant with F2008 standard"). I am guessing there was a standard increase in the project as I got a compiler error when trying to compile with F2003.

• Minimum version of Fortran required using gfortran: F2008
• How to compile with gfortran:
  1. First you can download the project by running in bash:

  git clone https://gitlab.com/QEF/q-e.git
  cd q-e
  

  2. Now you can compile the project by running:

  ./configure FC=gfortran CC=gcc F77=gfortran
  make all
  

        Where the paths to the GNU compilers are correctly substituted in.
• Does it compile with flang-new: No
  Configure script does not currently recognise flang-new as a compiler, and hence defaults to gfortran.

Versions:

• gcc version used: 9.3.0
• gfortran version used: 9.3.0
• flang-new, fir-dev branch, HEAD: fb8eb63
• clang-12: 12.0.0
• Quantum Espresso, develop branch, HEAD: 0048df7c99fc89df55d0c9405df063a9265ffbca
• Architecture for compilation: aarch64