In apolemme.com we have been using GraphQL a lot of times lately. Our clients have a request to have small services for all popular platforms. Mainly it is mobile and desktop. In some cases it can be exotic platform like POS terminal but it is different story :)

Theory

In microservice architecture there is such term as boundary level. The boundary provides your application bunch of capabilities:

  • authentication/authorization
  • rate limit (for instance 500 requests per second)
  • caching
  • collection logs/metrics
Image for post
Image for post
Example of boundary level approach

For sure, there are some cases when application can have loads of boundary levels. For example one boundary level encapsulates services that are in charge of user data and another ones are in charge of personal offers. …


I hope every data scientists knows how eigenvectors and eigenvalues are important in ML/DS area. But this post is rather for people who start studying data science from scratch and I would like to put my contribution just to help someone who seeks a simple answer. I won’t dwell on theory because I there are a lot of materials about the topic we will discuss in web, just want to focus on example.

The equation of a linear transformation:

Image for post
Image for post

Let’s look at the example a bit closer. Supposed, we have a matrix A:

Image for post
Image for post

That means that there is eigenvalues and eigenvectors that satisfy such…

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store