Re: [Databionic-esom-user] Parameter Selection for ESOM

[Michael D. J. <mic...@ya...>]

Dear Mario,
 
Thank you very much for your VERY QUICK response. It is very much appreciated.
 
I am glad that you mention that the size of the grid depends on the size of the dataset. I am aware that we need much more neurons than datapoints. However, is there an *approximate* rule for this? (E.g. If you have a dataset made up of 5000 instances, what would be a range for the size of the grid?)From your experience, what is the size of the dataset you use when the size of the grid is 50 by 82 and 70 by 110?
 
 
In addition, in terms of the size of the neighbourhood, what is a good approximate rule to follow? Moreover, in a grid where there are much more neurons than datapoints (e.g. a 100 to 1 ratio), what would the impact of a bigger or smaller neighborhood be?
 
I would like to thank you in advance for your continued support. 

Regards,
Michael
 

Mario Noecker <noe...@Ma...> wrote:
Hi Michael,

the best size of the grid depends on the size of the dataset. Using
emergent SOMs you need of course much more neurons then datapoints.
Mostly we use grids with 50 rows and 82 columns, or 70 rows and 110
columns. We realized grids with a rectangular shape offer the best
results.

We mostly use 20-30 epochs of training without relating to the gridsize.

if there are more questions, please ask.

mario

Michael Dell Junior wrote:

> Hi all,
> 
> Congratulations on the development effort for the production of such a
> good tool.
> 
> I have a few questions regarding the use of the tool:
> 
> 
> 1) Is there a "right number" for the size of the grid for convergence
> to occur?
> 2) Is there a relationship (or a rule of thumb) between the number of
> traning instances used and the right size of the grid?
> 
> 
> 
> Your help will be very much appreciated.
> 
> Regards,
> Michael Dell Junior
>
>
>
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