Month: April 2018

Training a restricted Boltzmann machine on a GPU with TensorFlow

During the second half of the last decade, researchers have started to exploit the impressive capabilities of graphical processing units (GPUs) to speed up the execution of various machine learning algorithms (see for instance [1] and [2] and the references therein). Compared to a standard CPU, modern GPUs offer a breathtaking degree of parallelization - … Continue reading Training a restricted Boltzmann machine on a GPU with TensorFlow →

Creating and signing a bitcoin transaction from scratch

In the one of the the last posts in this series, we have been able to successfully verify an existing bitcoin transaction. With the understanding of how this works, we should now be able to conversely create a transaction from scratch, sign it and publish it in the bitcoin network. Given an amount that we … Continue reading Creating and signing a bitcoin transaction from scratch →

Training restricted Boltzmann machines with persistent contrastive divergence

In the last post, we have looked at the contrastive divergence algorithm to train a restricted Boltzmann machine. Even though this algorithm continues to be very popular, it is by far not the only available algorithm. In this post, we will look at a different algorithm known as persistent contrastive divergence and apply it to … Continue reading Training restricted Boltzmann machines with persistent contrastive divergence →

Setting up and testing our bitcoin network

In the last post in my series on bitcoin and the blockchain, we have successfully "dockerized" the bitcoin core reference implementation and have built the bitcoin-alpine docker container that contains a bitcoin server node on top of the Alpine Linux distribution. In this post, we will use this container image to build up and initialize … Continue reading Setting up and testing our bitcoin network →

Learning algorithms for restricted Boltzmann machines – contrastive divergence

In the previous post on RBMs, we have derived the following gradient descent update rule for the weights. $latex \Delta W_{ij} = \beta \left[ \langle v_i \sigma(\beta a_j) \rangle_{\mathcal D} - \langle v_i \sigma(\beta a_j) \rangle_{P(v)} \right] &s=1 $ In this post, we will see how this update rule can be efficiently implemented. The first thing … Continue reading Learning algorithms for restricted Boltzmann machines – contrastive divergence →

Docker internals: process isolation with namespaces and cgroups

A couple of years back, when I first looked into Docker in more detail, I put together a few pages on how Docker is utilizing some Linux kernel technologies to realize process isolation. Recently I have been using Docker again, so I thought it would be a good point in time to dig out some … Continue reading Docker internals: process isolation with namespaces and cgroups →

Building a bitcoin container with Docker

When we are playing with bitcoin transactions, we need some playground where making a mistake does not cost us real bitcoins and therefore money. In addition, we might want to play around with more than one bitcoin server to see how networkings works and how the messages are exchanged in the bitcoin peer-to-peer network. There … Continue reading Building a bitcoin container with Docker →