Barcelona Chapter

Papers We Love BCN What was the last paper within the realm of computing you read and loved? What did it inspire you to build or tinker with? Come share the ideas in an awesome academic/research paper with fellow engineers, programmers, and paper-readers. Lead a session and show off code that you wrote that implements these ideas or just give us the lowdown about the paper (because of HARD MATH!). Otherwise, just come, listen, and discuss.

As a Papers We Love chapter we welcome everyone from the programming community for an evening of ideas, vibrant discussions and hanging out with your fellow travellers.

The Barcelona Chapter meets monthly at different locations throughout the city. Keep an eye on our page to find out the latest address.

Please make sure to RSVP before attending to make it easier for us to organize all correctly. You can find our schedule and RSVP here on

Papers We Love has a Code of Conduct. Please contact one of the Meetup's organizers if anyone is not following it. Be good to each other and to the PWL community!

Chapter Details

Sign-up: Please RSVP for meetings via

Twitter: @paperswelovebcn

Contact: jordi.montes AT upc DOT acm DOT com

Organizers: Jordi Montes, Pol Alvarez, Ivan Daniluk and Albert Serven

Sponsors and Organizers

Chapter Meetups

02/20 Lau Llobet on A Large-Scale Study of Programming Languages & Code Quality

Date/Time: 2020-02-19 07:00pm Location: Codurance - Barcelona

[Paper link](

Software engineers seem to develop a strange attachment for the tools they use. There seems to be consensus about "using the right tool for the right job" but the war about which tool is better suited for a job is a typical topic of discussion in our field. From Vim vs Emacs to OOP vs Functional programming most of the arguments seem to be based on feelings/abstract ideas instead of being backed by data.

Lau Llobet from Codurance will present a paper based on a large scale study of projects on Github trying to correlate different code quality metrics to the programming language that those projects are written in.

This will be a good occasion for discussing some controverted topics and try to shed light on an endless discussion.

About the author:

Lau Llobet discovered his passion for progra…

Read more about this Meetup

Papers We Love Barcelona November Meetup

Date/Time: 2019-11-27 07:00pm Location: TravelPerk - Barcelona

We're really happy to announce the new season of PWL Barcelona.

The event will have place at Travelperk's HQ

As you may know papers we love is a community of people who meet for discussing different computer science papers. However, the reality is that we use papers as an excuse to talk about interesting topics in CS. What we all have all in common is curiosity. Many of us are students, researchers or software engineers who spend 8h coding/solving problems.

Once per month we meet and talk about Computer Science/Software engineering. Our events are open to people from all levels so don't be scared by the word "paper".

In this event we will try a new format were we will talk about different topics and we will avoid the convention of one lighting talk + one paper talk. We will discuss:

- Industry-scale knowledge graphs
- Scaling static analysis @ Facebook
- The algorithm that changed quantum machine learning
- The success of the web
- …

Read more about this Meetup

PWL 11/2019: Dense Human Pose Estimation In The Wild

Date/Time: 2018-11-08 06:45pm Location: Verse HQ - Barcelona

We open this new season of Papers We Love Barcelona with a really hot topic: Computer vision.

We count with an expert in the topic: Carlos Andujar from the Universtat Politecnica de Catalunya. Carlos will discuss the paper DensePose: Dense Human Pose Estimation In The Wild from INRIA and Facebook AI Research. The paper can be download [here]( although there is no need to know anything about the topic before the talk.

Talk: DensePose: Dense Human Pose Estimation In The Wild

Dense human pose estimation is defined in this paper like the correspondences between an RGB image and a surface-based representation of the human body. Carlos will explain and discuss the last tecniques in this area like CNN-Based systems and fully-convunationa…

Read more about this Meetup

Expander graphs and applications

Date/Time: 2018-04-25 12:00pm Location: UPC campus nord - Edifici B6


More info:

Expander graphs and applications

Expanding graphs grew up in the context of communication networks. The notion of expansion is related to the growth of neighborhoods of sets in graphs and it is so natural that it found its place in a wide area of applications, some of them unexpected, in computer science, statistics and mathematics. The aim of the talk is to describe some of these applications in computation, random walks and in error correcting codes. A probabilistic argument shows that expander graphs are abundant, but explicit constructions turn out to be connected to sophisticated mathematical tools, which will be only summarized in the talk.

Nowadays there is a rich literature on the topic. The talk is based on the excellent…

Read more about this Meetup

Why the Greedy algorithm works?

Date/Time: 2018-03-21 07:00pm Location: Verse HQ - Barcelona

• What we'll do

Argimiro Arratia will peresent the paper Matroids and the greedy algorithm J. Edmonds (1971).

Argimiro Arratia is currently a professor of UPC and obtained his Ph.D in Mathematics (Wisconsin)
You can find more information about him following the next link:


A greedy algorithm is one of the simplest strategies to solve an optimization problem. It is based on a step-by-step selection of the best candidate (local) solution, in the hope that in the end of this process a global optimal solution is obtained. Greedy algorithms do not always output global optimal solutions, but for many optimization problems they do, in which case one says that the greedy algorithm works. Is there some criterion to know when it will work?

A result that we should love, and I will present in this talk, due to Jack Edmonds and published in 1971, state…

Read more about this Meetup

Searching with Dice: Skip lists and Randomized Binary search trees

Date/Time: 2018-02-28 12:00pm Location: Campus Nord UPC - Barcelona

• What we'll do
Papers we love Barcelona is back and we already have a list of amazing talks for the next months. The events will alternate between noon at the University and evenings at some company to be sure that everyone can attend.

Searching with Dices: a survey on randomized data structures by Conrado Martinez (

The usefulness of randomization in the design of algorithms has been known for a long time (Rabin's primality test or Karger's algorithm). Randomized algorithms usually yield algorithms which are simple, elegant, with guaranteed expected performance and practical.

Not many people know about why they work (theoretical basis) or how to analyze these algorithms. In this talk Conrado Martinez will explain two well-know data structures: Skip-lists (…

Read more about this Meetup

Data Streams as Random Permutations: the Distinct Element Problem

Date/Time: 2017-10-24 07:00pm Location: Verse HQ - Barcelona

Data Streams as Random Permutations (Paper) (

Presented by Jordi Montes, Research Engineer


Cardinality estimation has a wide range of applications from databases to network systems. The problem has been studied since the 80's and many algorithms have been proposed: Adaptive Sampling, HyperLogLog or Recorinality to say some of them.

In this talk we will discuss why cardinality estimation is an important problem, how it has been solved before and why looking at data streams as random permutations can be useful (Hint: This simple observation allows a wealth of classical and recent results from combinatorics to be recycled, with minimal effort, as estimators for various statistics over data streams.).

Talk will be based on this paper (

Read more about this Meetup