Why does same model produce different results on PC and MAC?

Using the Multiple Run Fitter, praxis, etc..
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mmushtaq
Posts: 16
Joined: Mon Jun 23, 2014 7:23 am

Why does same model produce different results on PC and MAC?

Post by mmushtaq »

Hi everyone
I developed thalamocortical model on MAC book pro with NEURON version 8.1. I ran same model on Windows operating system with NEURON version 8.0 but I found significant difference in both PC and MAC book results. Can somebody help me how can I fix this problem to get same/correct results on both MAC and PC. I will wait for your kind suggstions.
hines
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Joined: Wed May 18, 2005 3:32 pm

Re: Why does same model produce different results on PC and MAC?

Post by hines »

There are a number of ways that can happen ranging from double precision round off error differences in the pow function for mac and windows that then slowly accumulates in a chaotic model til a spiketime difference becomes apparent; to user error in handling randomness in mpi runs.
The most robust diagnostic method is to compare the spike raster of your mac and windows run to find the gid and spiketime of the earliest spike difference and then use ParallelContext.prcellstate of that cell to find the time where the first cell state difference occurs (check first to see if initialization is identical).
It is nice if you can reduce the model size to very small and still see differences. Of course, I may have completely missed the point as I know nothing about the structure of your model or what level of abstraction you are using.
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