Update SOM after training in R (question) about somoclu

[xgdgsc]

Similar to https://github.com/peterwittek/somoclu/blob/master/src/R/man/Rsomoclu.kohonen.Rd ?

[apastore]

Thanks! This is what I am doing for the training set. Where I am really struggling is to get the SOM Plot for the test data. I am using the map.kohone but it does not return the codes values so it is not possible to plot.

[peterwittek]

The R version of Somoclu is really just a computational back-end to kohonen, so visualization is left to that library. This is a fundamental difference to the Python version, where we develop our own visualization routines, so we have plenty of space to add convenience functions.

You are right, kohonen does not fill the updated map with much meaningful information:

new_data <- matrix(0, nrow=100, ncol=50)
new_map <- map(sommap, new_data)

It is easy to see that the result is correct, e.g., all new points get the same BMU, but you will not be able to visualize the result so easily.

[apastore]

How was wondering to re-compute the code of each SOM unit after mapping the Test set.
I have tried with the simple mean of the element map in the unit, but it look to me there is some sort of smooth.

Would be possible to have a R code to recompute the Som Unit Codes after update/test map?

Thanks!

Sent from my iPhone

On Oct 2, 2016, at 6:17 AM, Peter Wittek [email protected] wrote:

The R version of Somoclu is really just a computational back-end to kohonen, so visualization is left to that library. This is a fundamental difference to the Python version, where we develop our own visualization routines, so we have plenty of space to add convenience functions.

You are right, kohonen does not fill the updated map with much meaningful information:

new_data <- matrix(0, nrow=100, ncol=50)
new_map <- map(sommap, new_data)
It is easy to see that the result is correct, e.g., all new points get the same BMU, but you will not be able to visualize the result so easily.

—
You are receiving this because you authored the thread.
Reply to this email directly, view it on GitHub, or mute the thread.

[peterwittek]

I am sorry I don't understand the question. If you want to continue training the map with the test examples, just pass the current codebook to Rsomoclu.train with the new data. Adjust the radius and the scaling factors to avoid abrupt changes.