mpi_last: Properly end "mpi" workers before quitting R (e.g., at a...
In DrylandEcology/rSFSW2: Simulation Framework for SOILWAT2

Description Usage Arguments Notes Details

Properly end “mpi” workers before quitting R (e.g., at a crash)

1	mpi_last(gv)

`gv`	A list with at least one named element `p_has`. `p_has` is a logical value and indicates whether call is from a parallel run.

Code is based on http://acmmac.acadiau.ca/tl_files/sites/acmmac/resources/examples/task_pull.R.txt.

Ideally, we use Rmpi::mpi.exit() on exit, but we cannot as of Rmpi v0.6.6. Because rSFSW2 does not attach Rmpi, the function mpi.exit throws an error when it executes detach(package:Rmpi) which results in "Error in detach(package:Rmpi) : invalid 'name' argument".

Rmpi::mpi.comm.size(1) crashes with a segfault if there are no workers running because of the call .Call("mpi_comm_is_null", as.integer(comm), PACKAGE = "Rmpi").

Ideally, we would use Rmpi::mpi.close.Rslaves(). However, this function hangs our R session because of its call to Rmpi::mpi.comm.disconnect(); even wrapping this in try doesn't prevent it from hanging.

gv will usually be the package-level global variable environment SFSW2_glovars. This is because this function is registered as finalizer to the object SFSW2_glovars.

DrylandEcology/rSFSW2 documentation built on Aug. 18, 2020, 1:27 p.m.