The ring-buffer scaling is a function of connectivity and expected input firing rates in a particular network configuration, so pretty well independent of synapse type.

M

Michael Hopkins,
SpiNNaker project,
APT group, School of Computer Science,
University of Manchester,
Manchester M13 9PL
[email protected]:[email protected]

On 25 Aug 2015, at 10:11, Alan Stokes <[email protected]mailto:[email protected]> wrote:

different synapse types have different statistics and separate ring-buffer shifts to scale them with, so ideally, you should also be able to specify ring buffer sigma and spikes-per-second separately for different synapse types.

linked to #132#132

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Reply to this email directly or view it on GitHubhttps://github.com//issues/136.

You can do the scaling per synapse type i.e. if you know the firing rate of all the populations exciting this population and a different firing rate for all the populations inhibiting this population, you can do two separate calculations. We already do the separate calculations but we use a firing rate and sigma value which is fixed over the entire simulation. If you know more about your network, the ability to change this per population and per synapse type could help you to get better overall results; how much is to be seen, but it isn’t too hard to enable this (Alan has already done it per-population, per synapse-type is a bit more fiddly but doable).

From: Michael Hopkins [mailto:[email protected]]
Sent: 25 August 2015 11:45
To: SpiNNakerManchester/sPyNNaker [email protected]
Subject: Re: [sPyNNaker] Ring buffer sigma and spikes-per-second on a per synapse-type basis (#136)

The ring-buffer scaling is a function of connectivity and expected input firing rates in a particular network configuration, so pretty well independent of synapse type.

M

Michael Hopkins,
SpiNNaker project,
APT group, School of Computer Science,
University of Manchester,
Manchester M13 9PL
[email protected]:[email protected]mailto:[email protected]%3cmailto:[email protected]

On 25 Aug 2015, at 10:11, Alan Stokes <[email protected]<mailto:[email protected]mailto:[email protected]%3cmailto:[email protected]>> wrote:

different synapse types have different statistics and separate ring-buffer shifts to scale them with, so ideally, you should also be able to specify ring buffer sigma and spikes-per-second separately for different synapse types.

linked to #132#132

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/136.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/136#issuecomment-134552799.

Is this still valid?

I still don't think it is possible to do this. I don't know where it is relevant to do so.

We haven't completely moved to that yet, mainly due to issues with working out what the "atomic" weight will be! I think we will end up needing a combination of techniques e.g. maximum weight calculation, then minimum weight = max / 65536, and then also add in stochastic rounding to do things smaller than min weight. It will take a bit of effort to get these things done though!

I would think this can be closed if either #1386 or #852 are merged in the future.