## What does the L2 or Euclidean norm mean?

Here’s a quick tutorial on the L2 or Euclidean norm.

First of all, the terminology is not clear. So let’s start with that.

### Many equivalent names

All these names mean the same thing:
Euclidean norm == Euclidean length == L2 norm == L2 distance == $l^2$ $l^2$ norm

Although they are often used interchangable, we will use the phrase “L2 norm” here.

### Many equivalent symbols

Now also note that the symbol for the L2 norm is not always the same.

Let’s say we have a vector, $\vec{a} = [3,1,4,3,1]$.
Continue reading “What does the L2 or Euclidean norm mean?”

## Theano – stack smashing error

I’ve been working on getting my laptop‘s Nvidia GPU working with Theano on Ubuntu 14.04. The whole process of getting the GPU to work has been a quite a learning experience… (but more on that later)

After installing Anaconda (which includes Theano!), I start Python from the Terminal:

$python Python starts up correctly. I then try to import the theano library… >>> import theano and Ubuntu freezes up 🙁 So I restart the machine and try again to run Python and import Theano, but get the following error message: $ python
>>> import theano
*** stack smashing detected ***: python terminated
Aborted (core dumped)
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