Archive for outdoor swimming
Plouhais Beach [jatp]
Posted in pictures, Running, Travel with tags beach, Bretagne, Brittany, Côtes d'Àrmor, Channel, Erquy, jatp, Manche, outdoor swimming, vacations on May 14, 2021 by xi'an
At Guen Beach [jatp]
Posted in pictures, Running, Travel with tags Bretagne, Brittany, Cap Fréhel, Channel, jatp, Manche, outdoor swimming, Saint-Brieuc, Saint-Malo, sunrise, vacations on May 11, 2021 by xi'an
Tour de Paris [of pools]
Posted in Kids, pictures, Running, Travel with tags bakery, Joséphine Baker, outdoor swimming, Paris, Paris suburbs, running injury, Seine, swimming pool on April 25, 2021 by xi'an
As I am prevented from running since the beginning of this year, due to a ligament injury caused by an excess of kilometers run since the beginning of the (first) lockdown, I have started swimming most days I can find a free window of time. And an open swimming pool! While Paris and most of the suburban cities near me have a decent offer of (cheap) public pools, it is often a challenge to find one open at a manageable time. Meaning for me mostly in the early morning. The lockdown has obviously reduced opening hours and introduced restricted access, requiring a medical certificate for indoor pools, and I have thus being recently visiting a rather extensive array of pools to fit such constraints, since both nearby pools, at home and at work, are rarely available. Last week, I biked to the most exotic so far, namely a pool made from a barge standing on the Seine River. It is alas not yet outdoor, but not yet crowded either (if small and rather hot). By comparison, the nearer and wider pool at Porte d’Orléans is surprisingly crowded at 7am (but pleasantly colder) and the historical pool on Butte aux Cailles also gets quickly crowded and is missing its outdoor pool (but is close to a fantastic bakery!). Even careful scheduling does not always work as I sometimes find an unexpected closed door, as two weeks ago when Butte aux Cailles had emptied overnight or a few days ago when Joséphine Baker had a disfunctioning pediluvium enough to bar entry. (The outdoor 50m pool in Villejuif I used to go to has just reopened to the general public and is not yet overcrowded, despite milder temperatures.)
folded Normals
Posted in Books, Kids, pictures, R, Running, Statistics with tags Annals of Applied Statistics, EM algorithm, folded normal, La Butte aux Cailles, letter to the editor, maximum likelihood estimation, nlm, outdoor swimming, Paris, R, Rfast, swimming pool, wikipedia on February 25, 2021 by xi'an
While having breakfast (after an early morn swim at the vintage La Butte aux Cailles pool, which let me in free!), I noticed a letter to the Editor in the Annals of Applied Statistics, which I was unaware existed. (The concept, not this specific letter!) The point of the letter was to indicate that finding the MLE for the mean and variance of a folded normal distribution was feasible without resorting to the EM algorithm. Since the folded normal distribution is a special case of mixture (with fixed weights), using EM is indeed quite natural, but the author, Iain MacDonald, remarked that an optimiser such as R nlm() could be called instead. The few lines of relevant R code were even included. While this is a correct if minor remark, I am a wee bit surprised at seeing it included in the journal, the more because the authors of the original paper using the EM approach were given the opportunity to respond, noticing EM is much faster than nlm in the cases they tested, and Iain MacDonald had a further rejoinder! The more because the Wikipedia page mentioned the use of optimisers much earlier (and pointed out at the R package Rfast as producing MLEs for the distribution).
pool etiquette [and lane rage]
Posted in Statistics with tags breast stroke, etiquette, indoor swimming, Jean-Paul Sartre, l'enfer c'est les autres, outdoor swimming, road rage, swimming, swimming pool, training on March 15, 2019 by xi'an
A funny entry in The Guardian of today about what turns swimmers mad at the pool. A form (foam?) of road-rage in the water… Since I have started a daily swim since mid-December to compensate for my not-running for an indeterminate length of time, I can primarily if irrationally relate to the reactions reported in the article. About the pain of passing other swimmers and being brushed or kicked by faster runners oops swimmers trying to squeeze in the middle (of nowhere). Irrationally so because at a rational level there is nowhere to go really, except the end of the lane and back, which means waiting or turning back earlier not much of an imposition. But still feeling a sort of “road rage” when I cannot turn back and start again without delay… I have been thinking for the past weeks (while going back and forth, back and forth, dozens of times) of ways to rationalize the whole operation but cannot see a way to make all swimmers go exactly the same speed in a given lane, if only because most swimmers switch stroke between lengths. Except me as I can only and barely handle the breast stroke, thanks to lessons from Nick!, stroke than many seem to resent. To the point of calling for breast-stroke free lanes… Rationally, I think the problem is the same with every activity involving moving at different relative speeds on a busy lane. Runners get annoyed at breaking their pace, cyclists at braking or worse!, touching ground. It is just more concentrated in a 25m swimming lane on a busy day. (Which is why I really try to optimise my visits to the pool to be in the early morning or in the mid-afternoon. And again and again promise myself to skip the dreadful Sunday morning session!) L’enfer, c’est les autres, especially when they swim at a different pace!
