Questions tagged [self-organizing-maps]

Type of Neural network (unsupervised learning). SOM's goal is to convert high-dimensional data into low-dimensional, like 2D map, which can be understood by human. Impl. questions: neural network structure, learning parameters, performance, use, multi-thread optimization, etc.

Wikipedia:

A self-organizing map (SOM) or self-organizing feature map (SOFM) is a type of artificial neural network that is trained using unsupervised learning to produce a low-dimensional (typically two-dimensional), discretized representation of the input space of the training samples, called a map. Self-organizing maps are different from other artificial neural networks in the sense that they use a neighborhood function to preserve the topological properties of the input space.

137 questions
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How do I make a U-matrix?

How exactly is an U-matrix constructed in order to visualise a self-organizing-map? More specifically, suppose that I have an output grid of 3x3 nodes (that have already been trained), how do I construct a U-matrix from this? You can e.g. assume…
Spacey
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What is the difference between SOM (Self Organizing Maps) and K-Means?

There is only one question related to this in stackoverflow, and it is more about which one is better. I just dont really understand the difference. I mean they both work with vectors, which are assigned randomly to clusters, they both work with the…
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Hexagonal Self-Organizing map in Python

I am looking for hexagonal self-organizing map on Python. ready module. If one exists. way to plot hexagonal cell algorithms to work with hexagonal cells as array or smth else About: A self-organizing map (SOM) or self-organizing feature map…
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Pattern Detection in Time Series Data

I have a data frame representing a time series like for example: timestamp: 1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28... value: 0|0|3|6|3|3|6|3|3|6 |3 |0 |0 |0 |1 |3 |7 |0 |0 |1 |3 |7 |1 |3 |7 |3 |6 |3 ... The goal…
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Self Organizing Map (SOM) Implementation

I'm looking for a C, C++ or Java based SOM implementation with licensing applicable for commercial use (non-zero cost is okay). So far I'm aware that there exists SOM_PAK (from Kohonen), but the licensing forbids commercial use. Is anyone aware of…
Mark Elliot
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Best way to create a collage (in Java)

I want to create a collage of photos. Similar to this image (think of photos instead of those colored rectangles): The collage should be constructed from the following information. We have a 2d map of slots and set of images. The map (in this case…
Renke Grunwald
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Self Organizing maps Vs k-means

Does anyone know how well does Self Organizing Maps(SOM) compare to k-means? I believe usually in the color space,such as RGB, SOM is a better method to cluster colors together as there is overlap in the color space between visually different colors…
Vinayak Agarwal
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Convergence criterion for (batch) SOM (Self-Organizing Map, aka "Kohonen Map")?

I like to stop the execution when Batch SOM becomes converged. What error function can I use to determine the convergence?
S.N
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Why is this Python script running faster in the CPU than in the GPU?

I'm using Python's library somoclu to train a self-organising map using Python. The library allows users to perform the training either on the CPU (Intel Core i7-8700) or on the GPU (GeForce GTX 1080 Ti). I noticed that the CPU was running the…
Tendero
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Is it right to normalize data and/or weight vectors in a SOM?

So I am being stumped by something that (should) be simple: I have written a SOM for a simple 'play' two-dimensional data set. Here is the data: You can make out 3 clusters by yourself. Now, there are two things that confuse me. The first is…
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Is the location of a neuron in a Self-Organizing Map dependent on its weight?

I've looked at a lot of theoretical examples of SOMs, but one thing is not really clear to me: is the location of nodes dependent on their weights? For example, will nodes with a larger weight be on one side of the map, while nodes with a smaller…
Dominique
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what is the difference between Self Organizing Maps and neural gas

I am finding it difficult to understand the difference between Self Organizing Maps and neural gas. I read the Wikipedia article and Neural Gas Network Learns topologies article. The SOM algorithm and Neural Gas algorithm looks so similar. In both…
clarkson
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Why is there a need for the number of iterations in the Self-Organizing Map?

:) While I was defending my thesis proposal, one of my professors asked me why do we have to specify the number of iterations in SOM? He said, there should've been a convergence criterion for us to stop training. However, I understand that we do not…
Chester
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Matlab SOM Toolbox U-Matrix Visualization

I'm using the SOM Toolbox to analyze data collected from a database of cars. My problem is when visualizing the Unified Distance Matrix. Quoting the documentation for som_umat: Compute and return the unified distance matrix of a SOM. For example…
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How to map/plot new data onto a trained SOM map?

After training a SOM, how can you plot new data onto the SOM and visualise how it maps onto the SOM? Ideally, I would like for it to be plotted with the corresponding classification colour and node location. identify() has the capability of…
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