2 of 17

Agenda

Introduction from "new" members
NEURON News / Announcements
Dynamic MPI Support in CoreNEURON
Status of GPU support in Python wheel
WSL and Python wheels
Inclusion of nrntest and external test repos
Paper results / Hippocampus model
Upcoming SFN Poster
Ongoing NEURON work
Next Meeting

3 of 17

Introduction From New Members

4 of 17

NEURON News / Announcements

5 of 17

Dynamic MPI support in CoreNEURON

What is dynamic MPI?

Choice of which MPI implementation to use, if any, made at runtime
Improves wheel portability. MPI not shipped with NEURON

Why is that needed?

MPI is an API, not ABI, specification

User machine

[Core]NEURON

OpenMPI libmpi.so

MPICH libmpi.so

(not present on this

user’s machine)

libnrnmpi_mpich.so

(attempting to load

this would fail)

libnrnmpi_openmpi.so

“openmpi”

--mpi Do we want MPI?

Load at runtime

6 of 17

Current NEURON Implementation

Relies on legacy scripts to generate headers: mkdynam.sh

grep through the existing files and extract function names�

Uses macros to switch between function calls or pointers�
Not robust and not easy to extend

7 of 17

New Implementation in CoreNEURON

More modern C++ approach
All coreneuron::nrnmpi_xyz(a, b, c) methods are instances of the same helper template
Depending on compile/runtime options, this despatches to a function pointer that was linked either at compile time or run time.
Give us the chance to nicely split code related to mpi. Before if --mpi was not given but MPI was available some mpi code were run.

8 of 17

GPU Support in Python Wheel

First working draft of python wheel with GPU support

can run with/without MPI and with/without GPU�

Primary/first target is to run simulations

i.e. Jupyter based, interactive usage won’t be possible right away
need to use special executable created from `nrnivmodl mod`

nrnivmodl -coreneuron <mod>
./x86_64/special -python or ./x86_64/special -python test.py�

Ongoing PRs, target to mergy early next week

If want to try pre-alpha version to provide feedback, ping us on Slack

9 of 17

WSL and Python Wheels

Documentation here�
Thanks to Robin!

10 of 17

Inclusion of nrntest

Standalone repository containing number of tests

HOC, Python, NMODL, CVODE�

Was executed manually sporadically / during releases�
Now integrated into neuron: make test�

cleanup of old scripts
fixes for difference compilers - ascii result files & floating point discrepancies

11 of 17

Inclusion of other external tests

Move away from using git submodules for external test/model repositories
Can add extra tests without forcing everyone to download them all the time
Benefit from NEURON’s CMake/CTest helpers, less need for ad-hoc scripts
Example: nrn#1439 integrates some tests of Blue Brain Project mechanisms, these are now tested in the CI [currently only of CoreNEURON]