Computing Automorphic Numbers

In our lab, we like to tease each other with fancy riddles. In our kitchen, we have a large wooden box, filled with some chocolates and locked by a 4-digits lock. Those who crave for some sugar will just need to solve the riddle and unlock the box.
The last few riddles involved a particular family of numbers which are called automorphic, and the complexity of such riddles was increasing with the size of those numbers in terms of the number of digits. For instance, in the last riddle, we were asked to compute a number with 44444 digits, requiring an enormous computational power.
In this post, I will show how I developed the algorithm that allowed me to solve the riddle.

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Export Graph in R via JSON

This post presents an easy solution for exporting and importing a graph object of igraph library. In its previous versions, the library used to have the save and load functions in which you could respectively export and import the graph object [1]. Although they seem to not be in the library anymore, the documentation states: “Attribute values […]

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Clique Percolation Method in R: a fast implementation

Clique Percolation Method (CPM) is an algorithm for finding overlapping communities within networks, intruduced by Palla et al. (2005, see references). This implementation in R, firstly detects communities of size k, then creates a clique graph. Each community will be represented by each connected component in the clique graph. Algorithm The algorithm performs the following […]

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XMLResearcherProfile

  XMLResearcherProfile is a technology for tracking and presenting academics’ profile. In its early stage, it allows to record all the published papers (in proceedings, journals, posters and phd thesis) within a single XML file and afterwards it allows to format them as a list in a HTML page. Using specific XML tags it is possible to describe […]

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Italian translation of official RStudio cheatsheets

I recently joined the community of RStudio, which is an Integrated Development Environment (IDE) for R (an open source statistical language to make sense of data). My contribution is providing the Italian Translation of their cheatsheet (Schede di Riferimento).

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Tumblr RSS Widget

Tumblr RSS Widget is a web page able to read feeds from Tumblr blog and ready to be included in your web page. It exploits RSS feeds generated by Tumblr, then it parses and reorganizes them in order to improve the reading.

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Pie Chart with QWT

Pie Chart with QWT is a little application able to show a pie chart using QWT library. This idea (allow me to use it) is born because in a project that I was developing I used QWT to make some plots and when I looked for a pie chart there only one chance to get […]

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Grid Search SVM

The Grid Search SVM is a Java-based application that allows to perform the grid search of an SVM classifier. According to the section 3.2 of (Hsu, Chang and Lin: A Practical Guide to Support Vector Classication) [1], the grid search consists in identifying the best (C, γ) values that allow to classify accurately the unknown […]

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FFmpeg Recorder

The FFmpeg Recorder is an home-made application that lets to record a movie. It is based on the FFmpeg applications to acquire the streams coming from the webcam and microphone.

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\n-Remover

The \n-Remover is an home-made application that lets to remove the newlines from a text. Maybe this could be the most useless application ever thought but sometimes when you have it why not use it. This application has been developed because when you do copy and paste from a pdf file to a text file, […]

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