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The newsletter of the SIE de Investigación y Enseñanza N. 63 - Summer 2018

Supercomputing statistics for semester 2018A

As expected, the upgrade of the LaPalma Supercomputer (to LaPalma v3) has had a big impact on the IAC Supercomputing statistics. The total amount of hours consumed by IAC users in that Supercomputer in 2018A was 2,766,681.70, almost 8 times the time consumed in 2017A (which was the last complete semester for LaPalma v2). This amount is slightly bigger than the sum of all consumed hours in all IAC's supercomputing resources (LaPalma v2, TeideHPC, HTCondor, etc.) in each of the last semesters. However, it is only the 41.3% of the total execution time on LaPalma in 2018A, the other 59.7% (3,931,064.85 hours) being accounted for by RES users (the Spanish Supercomputing Network): the total amount of hours computed on La Palma in 2018A was thus 6,697,746.55 hours.

While the number of CPU hours used up by HTCondor is more or less the same as in the last semester, with 947,276.70 total hours, the biggest impact was felt by TeideHPC, where the total amount of hours (1,445,672.17 hours) decreased about 17% compared to 2017B. This was something we were expecting, because even if both systems have similar characteristics regarding to CPU, architecture, etc., the absence of limitations in the usage of LaPalma and the faster data transfers make the latter much more attractive to our local users.

Finally, the total amount of hours used by the new Severo Ochoa Supercomputer was 462,608.36 (on the 192-core computing node only; GPU calculations are not measured yet). Since the machine was added last fall, we cannot compare it with past usage. Also, we began to measure the usage of the various "burros" a few months ago, so we hope to add soon an estimation of the consumed hours on those machines. In the meanwhile, you can check the real-time load of some of the "burros" by pointing your browser to http://carlota:81/burros/

Adding up all these numbers, the total amount of CPU hours used by IAC researchers in semester 2018A was 5,622,238.93 hours, 4.3% more than in the whole 2017.

New web-based observations management applications

As the amount of observations and astronomical data grows exponentially, the use of suitable designed databases to manage all these data becomes fundamental. Aware of this, during the last year we have been busy developing several web-based applications to plan and manage observations for IAC research projects. An example is the application developed for the KESPRINT Consortium, a multi-national collaboration for the discovery, confirmation and characterization of planet candidates from the Kepler's K2 mission, which enables the team to organize hundreds (planned to become thousands) of exoplanet candidates and observations from K2 and TESS, as well as to produce transits observability ephemerides based on several parameters, aimed to optimize the scheduling of new observations. The MuSCAT2 observations tool, on the other hand, archives the targets and observations of TCS's instrument and can produce observability reports helping plan the priority observations every observing night, furthermore allowing real-time access to the data and logs produced by MuSCAT2 .

These tools make it possible to manage large amounts of observations and to plan new ones with collaborators and contributors all around the world. So, if you deal with many and constantly growing data, maybe a database-based application can help you not to drown in them.

Personnel movements

Antonio Dorta, SIE's supercomputing postdoc, will be leaving the IAC at the end of August having secured a permanent position as high school teacher. Let's congratulate him on this important accomplishment, and wish him all the best in his new job! Those who want to say goodbye in exchange for a chocolate or bonbon, please drop by our office on Wednesday 8th, Antonio's last working day at the IAC before going on holiday.

Accessibility of websites

"Web accessibility refers to the inclusive practice of removing barriers that prevent interaction with, or access to websites, by people with disabilities. When sites are correctly designed, developed and edited, all users have equal access to information and functionality." The Wikipedia page about Web Accessibility starts with this paragraph, and then explain what Web Accessibility means in practice. Just the introduction is well worth reading. We all know directly or are familiar with people on a wheelchair, and the many physical barriers they encounter in their daily life (for instance, steps and curbs that block a person with mobility impairment from entering a building or using a sidewalk). Well, similar barriers may find, for instance, a blind person trying to read a website that does not comply with the most basic accessibility criteria. Just a couple of examples to illustrate the problem.
  • A website is identified as being in english (by the lang=en tag in the head section). A blind person uses a screen reader which will use the appropriate voice depending on the language set (in this case something like a native english speaker). Let's say some page in the site contains text in spanish, which however is not identified as such: it will be read with an english accent, which may sound funny but certainly makes it difficult or impossible to understand it.
  • The website contains the typical image of a house, which clicked will lead to the home page. Unfortunately, a screen reader cannot interpret image and won't make sense of that little house icon. A simple alt tag added to the image, such as alt="Back to Home Page" or similar will be all it needs to make it accessible.
So, whenever you receive a mail with an assessment on the accessibility of you website, together with a list of issues and corrective actions, don't think of it as one of those pointless requirements devised by some halfwit bureaucrats whose only purpose is to waste our time, but as an opportunity to make our websites accessible to as many people with diverse abilities as possible.

Convert handwriting to LaTeX code

If it so happens that you wish to use a symbol in LaTeX and you don't know what its LaTeX code is, or if you want to print an equation, but you don't get the expected result, you can try one of the applications listed below, which allow you to draw the symbol and/or equation on the screen using your mouse, and automatically output the corresponding LaTeX code:
SIE de Investigación y Enseñanza :: N. 63 - Summer 2018 - Contact: