Weekly Picks

June 21, 2012 § Leave a comment

We try to read every blog post that goes through For the Weekly Picks, we collect posts in one category from last week to give you an impression of what the mathematical blogosphere has to offer. (Read this for more information on this change.)

Last week, we focused on “Pure Researchers.


Community, Art


  • Gaussianos (translation) explains how Zeckendorf’s representation by Fibonacci numbers connects to converting miles and kilometers.
  • ∑idiot’s Blog gives you Latent Dirichlet Allocation from scratch.
  • At Division by Zero, Dave Richeson found a nice puzzle with a squarable region by Leonardo da Vinci.


Mid week update

August 17, 2011 § Leave a comment

After the big update last week not a lot has happened. We had to clean up a few smaller issues but nothing out of the ordinary (and thankfully no down time). The next few weeks will be slow because we’re all traveling.

Different code, different problems

The old code only ever used the live feeds — they were downloaded, processed to generate the pages and then discarded. This had some major drawbacks, especially for the stats since most feeds are too short to represent a whole month of posts.

Now that we’re temporarily storing information, we have to deal with other issues. For example, wordpress users mostly have rss feeds which do not offer a timestamp for the last update. So if something changes in a post (say, somebody adds a PlanetMO tag), the feed does not easily reflect this and our database does not update because checking more than the timestamp is rather cpu heavy. There’s not much we can do except appeal to bloggers to use the atom protocol, but since we’re only keeping information for a month, we hope it’s not a huge issue. After all, most posts never see an update.

Database update

After last weeks huge update only four new feeds found us and were added today.

The math/maths podcast

Musing Mathematically

An Ocean Of Knowledge An Inch Deep.

Dr. Nicki’s Guided Math Blog

The update hath hitteth

August 8, 2011 § 4 Comments

The long awaited update is finally online.

After a bit of work, even more debugging and a lot of testing we have uploaded the new code. Even though the appearance has not changed much, the underlying technology is now much more efficient and reliable and will allow us to add more features in the long run.

The key: more data storage

The key change was the internal storage of all your regularly updated feeds. This is now done properly and allows much more reliable performance than our old code.

But it also helps with our features. For example, the statistics have always depended on the current rss-file from each blog. Almost all the statistics were simply wrong because the feeds are too short to store the information we needed for, say, the monthly count. Now that the feeds are stored in our database we can give more accurate counts.

Other cosmetic changes

The few cosmetic changes happened, e.g., on the “By Date” views that got a small menu. Most prominent are the changes to PlanetTAG. The tag cloud now has more entries and the dominant terms (such as “mathematics”)  have been filtered out. We hope it will be more useful that way even though tagging is very inconsistent across the mathematical blogosphere.

Database update coming up

With these changes the code is finally efficient enough again to take on a whopping 100+ new database entries — getting us well on our way to 500 entries!

Stay tuned for more later this week!

Weekly almost-update

July 28, 2011 § Leave a comment

Are we there yet?

Our re-write is complete. We’re testing the our code whenever we find time, but if all goes well, the new code will go online this weekend (and we will, of course, post about this here). There are some minor bugs we still need to hunt down and some cosmetic changes to fix.

All in all, we’re very excited to see if the code behaves as expected once it’s live. If all goes according to plan, virtually nothing will change on the surface of, but things will finally become smoother under the hood.

We’ll keep you updated!

Weekly non-update

July 21, 2011 § 1 Comment

We thought you wouldn’t mind if we updated you a little on our coding work.

Yesterday we had one of your almost-weekly meetings, working across the big pond to work on the code. It has been four weeks since we started working on this major update.  As it turns out the better description would be “complete re-write”.

Since is our fun project and we’re all doing mathematical research to make a living, we don’t have a lot of time to work on the code. We realize that this is sometimes an inconvenience for the community, especially those 100 blogs that have been stuck in our delayed database update. As we wrote before, the size of the database as brought our puny amateur code to the breaking point. We cannot update the database before we finish this re-write or else the site will become very unreliable. Again, we’re sorry for any inconvenience that is already apparent (such as the infamous “white boxes” in the “by type” view).

The good news is that we’ve had a sort of debugging breakthrough yesterday when we finally solved a few major problems, getting the date view and type view going again. Next week we’re hoping to finish the debugging. We will test for at least one week locally before we push the update. So if all goes well, the biggest update so far (hey, we might even drop the “beta” 😉 ) will be finished this month.

Small Database update

April 26, 2011 § Leave a comment

We just added some new entries to our database– that’s 263 entries now.

So a quick shout out is in order.


Weekly update

April 21, 2011 § Leave a comment

Slowly we’re getting back into a weekly rhythm… What’s new?

We just deployed an updated version of our code to the app engine. (Un)fortunately, there’s nothing visible — yet.

After last week’s quota problems, we think we have identified and fixed the latest bug. If you care, here’s what happened. For safety reasons we had started to keep sanitized copies of each entry in the memcache (for things like PlanetMO). But some bloggers write such long posts that this increase blew the 1MB limit of GAE’s memcache. This in turn collided with the real bug — we had forgotten to catch such an error and good old GAE just retried to download and process such feeds indefinitely… Not too surprisingly, this led to an overload in incoming bandwidth and CPU-time.

So the only visible change with this update is that the “problematic” blogs (among them Timothy Gowers’s) are back in our database!

On the bright side, we are almost ready to release a couple of new features. So stay tuned for our next update (or hunt our code to find these easter eggs and let us know in the comments if you like what you see!).

New feature: Introducing PlanetMO

April 15, 2011 § Leave a comment

Well, when bugs bring you  trouble, add more functionality! We are happy to announce a new feature on PlanetMO!

Recently, I was involved in a discussion on meta.mathoverflow regarding a possible ‘corner’ for discussions close to mathoverflow. The typical example is a question off topic for MO but nevertheless interesting. Where to go to have a discussion? And how to find those discussions?

Among the many tools that were mentioned, an_mo_user (who had started the thread) suggested a ‘Planet Mathoverflow’ similar to Planet Debian, Planet Gnome etc (and not to be confused with the encyclopedia PlanetMath). The idea would be that somebody who is interested in continuing the discussion of a closed question could simply write a blog post, post a link to that post in the comments of the question and moderate the discussion on the blog. Using a suitable tag, this blog post could appear on a Planet-like site. This would solve several problems: the discussion would  be clearly away from MO, there would be no need for general moderators since the blogger would be in charge and finally visibility of such discussions would be achieved through the planet.

After checking with Fred and Felix, I offered that we could realize such a PlanetMO on Thanks to Felix’s efforts and some co-operative fine tuning we are able to release this new feature into the wild today! On you can now check out (in full length) posts from bloggers in our database which were tagged with ‘mathoverflow’, ‘MO’ or ‘PlanetMO’ (although there are only a few right now).

We understand if people feel the full length is a little intrusive. We plan to restrict the Planet to the ‘PlanetMO’ tag soon so that people can use the ‘mathoverflow’-tag without appearing on PlanetMO. But to actually show the advantage of this feature, we are including the other tags for a couple of days.

We hope this feature is helpful, especially for the great community on mathoverflow!

Weekly update

April 12, 2011 § 2 Comments

Well, not much to say this time around (but we’re working on a cool new feature).

We were all rather busy but finally got around to adding some new blogs to our list.


Midweek update

March 30, 2011 § Leave a comment

Either consider this a belated weekly update or a brand new midweek update, but there’s lots to talk about!

If you visited in the last 12 hours you might have noticed that we finally launched the promised big update! Not everything we’ve planned is there yet (especially the uncluttered category view needs more patience, but we promise it’ll be worth the wait). So what’s changed? Well, you could look at Felix’s github since his repository is usually the reference for our code, but let me tell you right here 🙂

View by Stats

The most obvious update is our new view by statistics where you can finally see who posts how much and especially where discussions might be going on. The statistics are very basic — we’re only counting numbers of posts and comments per day, week and month. In particular, you cannot guess from the numbers whether the posts are short or long and we do not give the amount of comments per post or their content.

Right now we do not have the time for more complex statistics. This is mostly due to the practical complexity of having all sorts of different sources. Take for example the comment feeds. Some bloggers (and/or their blog engines) offer a comment feed per post, some don’t, sometimes that information is in the feed for the posts, sometimes it isn’t, sometimes it contains the actual comments, sometimes just “X commented on post Y”. In other words, there would be a lot of individual hacking necessary to extract more information from this “mess”. Maybe we’ll do it in the future, but right now it was not a realistic goal.

Another important complication can be seen from multiples of 5 occurring frequently in the stats. This is due to the fact that a lot of bloggers restrict the amount of entries in their feeds. So the numbers are often not reliable  — hence more complicated statistics made even less sense.

Twitter integration

On our front page you can now find a twitter widget that keeps you updated on our twitter list of math bloggers with a twitter account. With this at hand we decided to drop the microblog section from the category view — they never really fit because microblogging is much more dynamic. There’s only one problem: it meant loosing Terry Tao’s Buzz feed. We’re looking for a good way to re-integrate Terry Tao’s Buzz again at a later time — all suggestions welcome, of course.

New Feeds

We used to have two rather large RSS/Atom-feeds. We decided to offer more options — now you can decide to, e.g., only follow group blogs or only follow the institutional content. This hopefully makes it easier to find what you’re interested in. And of course you can still easily combine our feeds using your favorite feed reader.

The Database

As promised since virtually Day 1 we finally found a convenient solution to share our database. The problem was, of course, to keep things up to date. Hence we created a link where you’ll always get the latest online version of our collection right from the appengine. So if you feel like giving us some competition, it shouldn’t take more than 5 minutes to register a new app, upload our open sourced code and our database to get you going. Of course, we hope you’d rather join our team to make the site more useful 😉

The little things

Finally, there were some details that changed under the hood, e.g. the website finally caches, some bugs were resolved.

In any case, we’d like to  invite you to take a look around

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