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The newsletter of the SIE de Investigación y Enseñanza N. 67 - November 2021

New Overleaf "Collaborator" licenses

We have recently bought a pack of 50 Overleaf licenses, of the "Collaborator" type, which allows for up to 10 co-authors for a given project (paper). The Collaborator plan also includes benefits such as Real-time track changes, Full document history, Advanced reference search, and more (see for further details). Some useful material for Overleaf users can be found at (worksheets) and (upcoming webinars along with recorded versions for play on demand).

About 25 licenses have been already assigned to those users who expressed their interest in a paid Overleaf license, in the poll we did last year. Thus there are about 25 licenses available right now. If you want to get one, please send an email to Licenses will be assigned on a first-come first-served basis.

New PCs at CCA

The CCA (Centro de Cáculo de Alumnos) had about 30 desktops PCs used mostly by students enrolled in the Astrophysics Master. Besides being old (> 5 years) models, they were installed with Fedora 21, an unmaintained distribution, where no new software installations or updates were possible. For this reason, 29 new desktops PC have been bought to replace the old ones. They have been installed with Ubuntu 18.04, the same Linux release installed at the IAC, which eases considerably the burden of maintaining all the installed astronomical software packages. To make it easier for students to access those PCs remotely, an xrdp server has been installed, which allows a remote connection using an RDP client, available for all platforms: the Microsoft one for Windows and Mac, Remmina for Linux. Basic set-up and usage instructions have been published in the ULL Virtual Campus.

Supercomputing statistics for 1st semester 2021

The usage of HTCondor has increased considerably in the first semester of 2021, with about 735.000 CPU hours, compared to about 430.000 CPU hours in the second half of 2020. The 2021-S1 usage data mean that, on average, about 170 slots were used by HTCondor, approximately 25% of all available slots. We also note that, thanks to the arrival and installation of several new Linux servers (bought by research projects), the current HTCondor pool (as of October 2021) includes more than one thousand slots.
As for LaPalma, about 4 million CPU hours have been consumed by IAC users in the first semester of 2021. It corresponds to less than 50% of the total CPU time available to the IAC in that time period; on the other hand, non-IAC RES users have consumed about 90% of all the available CPU-hours.
TeideHPC registered a way lower usage, since in the first semester of 2021 only about 160000 CPU-hours were consumed by IAC users, which is less than one tenth of the available CPU-hours for the IAC community.

MWE: Minimal Working Example

If you have a problem with a software package (a python script that aborts, a latex file that does not compile, an IDL program giving weird results, etc.), the best way to get help is to provide a so-called MWE (Minimal Working Example), that is the most simple and short self-contained example (including all the necessary auxiliary files) that allows the person helping you to reproduce the problem. If for example a complex python script fails to parse a given file, you should send only the part of the code that reads the file, eliminating all the code that processes the input data; on the other hand, do not forget to provide the file to be read. If a Latex table in your thesis ends up misaligned or truncated, do not send the whole chapter or the entire thesis, but just the relevant latex code with the table and the proper context. Failure to follow these simple recommendations may turn a potential simple fix into a complicated endeavour which unavoidably delays finding the solution to the problem.

SIE de Investigación y Enseñanza :: N. 67 - November 2021 - Contact: