NMSplit90

This respository hosts some F90 programs to compute splitting functions of normal modes due to Inner Core anisotropy. Some of the original code was translated from Jeroen Tromp's old F77 code, hence the emphasis on '90'.

Repository overview and structure

Within this repository are two directories, described below:

• get_mode

  • This directory contains the program test_modes. The majority of this code was translated from F77 with some updates to the MINEOS read format to enable compatibility with the most recent version of MINEOS.
  • The program loads a mode and conducts radial integration to test the normalisation of the radial eigenfunction in accordance with the MINEOS normalisation conventions

• specfem_mesh

  This directory contains a number of programs

  • read_mesh
    This is the main driver program, which evidently needs renaming. So far, this code has the following functionality:
    • Reads MINEOS radial knots
    • Reads SPECFEM mesh
    • Loads mode eigenfunctions
    • Computes mode displacement at each GLL point in the mesh
    • Computes mode strain at each GLL point in the mesh
  • split_mesh
    The goal of this package is to compute splitting functions due to inner core anisotropy, which requires evaluation of the integral $$ \int_{V} \mathbf{\tilde{\epsilon}}k^{*} : \mathbf{\gamma} : \mathbf{\tilde{\epsilon}}{k'} : \mathrm{d} V $$ between two modes $k$ and $k'$. We therefore need to integrate over the entire inner core.
    • The current problem is that while the SPECFEM_GLOBE mesher will do the load balancing and mesh generation, the innermost cube of the inner core is shared between each process.
    • Note that this is true when using 6 processes. If you use more processes then only parts of the central cube are shared between different processes.
    • For simplicity, I therefore use 6 here.
    • Split mesh therefore processes these mesh files so that the central cube is only stored on one process, while the other processes contain only the parts that are non-overlapping in the original mesh.

Runtime considerations

• The mesh is read in from the directory hard coded in params.f90, stored in the variable datadir. If you run split_mesh it will output the new mesh files into ${datadir}/sliced. Once you have run this program, you would then need to edit your datadir to ${datadir}/sliced so that it is then loading the new mesh from the sliced directory.