Flying memes

Archive for the ‘Algoritmi’ Category

Plotting the characteristic polynomial of a matrix

Wednesday, June 28th, 2017

Next step is determining the roots of the characteristic polynomial of a matrix. Before working on extracting the roots using Newton’s method I wanted to be able to visualize the function.

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Determinant of a matrix in JS

Saturday, June 10th, 2017

I’m currently reading Deep Learning, from Ian Goodfellow, Yoshua Bengio and Aaron Courville. While reading I got interested in calculating the determinant of a square matrix, I know there are many existing libraries to do that but the algorithm looked simply enough to give it a try.

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How to render a dynamic animated Delaunay triangulation

Sunday, May 4th, 2014

A friend of mine recently asked if I can create an animation out of this nice example; the first thing I did was wrap the render function around a requestAnimationFrame and add a random speed factor to all the vertices at every iteration.

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Angular.js prevent an invalid form submission

Saturday, March 1st, 2014

Angular.js does an excellent job on preventing a form submission when invalid but only if the action attribute is not present, otherwise we have to implement a few tricks to achieve the same behaviour.

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Useless bu fun: Encoding video to CSS

Thursday, March 14th, 2013

I spent part of the last weekend on this experiment that startet with a question: it is possible to convert a video to a stream of CSS properties ? Surprisingly the answer is yes. We can dump each video frame to a canvas and then create a special (and very long) multiple background property (one background for each video row) where each pixel is created using a 1px size gradient.

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Migrating a single site of a wordpress multisite instance

Sunday, October 28th, 2012

Recently I had to deal with a WordPress multisite instance, the task was moving the contents of one of the sites hosted on the network to a local copy, update them and the re-move them to the production server.

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Handling thousands of pics from a mobile device

Sunday, November 27th, 2011

Lately I’ve been involved into a fascinating project called PepperTweet which consist in extract and visualize streams of pics from twitter starting from some search keywords.

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HTML5 Augmented Reality: fuzzy results

Thursday, May 12th, 2011

I spent a few hours trying to figure out how to deal with the brand new deviceorientation API in order to obtain a nice Augmented Reality effect. First I searched on how to convert Euler Angles to Cartesian Coordinates and I found a nice article about that, then I downloaded the very nice Sylvester library which lets you compute matrix operations in Javascript.

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I’ve just checked in at WC2010 Johannesburg Stadium from home

Saturday, June 12th, 2010

Thanks to Uncle Pear suggestion I realized that you can easily check-in in every Foursquare venue simply invoking its id using the API, to try this behavior I checked in at Johannesburg  WC2010 stadium from my home in Italy.

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A semantic experiment for separate good from bad.

Tuesday, May 4th, 2010

Yesterday was sunday and I came up with a fascinating idea: what happens if I use wordnet to measure the distance between two words ? By assigning weights to all the relation types and by navigate this relations graph I thought to be able to measure the distance between a word and the others in terms of the minimum sum of weights of the edges between each pair made of the chosen word and another.

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