Skip to main content

Novinky z projektov

Perfect Cuboid 3rd Batch status

yoyo@home - Št, 19.04.2018 - 00:00
If a perfect cuboid exists, its body diagonal exceeds 252.
Kategórie: Novinky z projektov

New LLR apps

PrimeGrid - Ut, 17.04.2018 - 05:57
We have upgraded the version of LLR used on all of our LLR projects to LLR v.3.8.21. As with the previous version of LLR, it is available in 32 and 64 bit versions for Windows and Linux, and 64 bits for Mac OS. This release has two major features: * Support for AVX/FMA3 on AMD Ryzen CPUs. You can expect about a 10% increase in speed on Ryzen processors as compared to earlier versions of LLR. * A rare bug that sometimes caused errors when using multithreading has been corrected. If you are using app_info.xml (aka anonymous platform) please upgrade to the latest LLR. The wrapper is unchanged. Upgrading is not mandatory, but is strongly recommended. If you are not using app_info.xml, you will automatically get the new version with your next LLR task and no action is necessary on your part. If you're not sure if you're using app_info.xml you're almost certainly not using it, and no action is necessary.
Kategórie: Novinky z projektov

Improved Database Stability

Milkyway@Home - Po, 16.04.2018 - 21:21
Hey Everyone,

I made some more configuration updates to improve database stability. If you notice any database errors, please post about them here.

Kategórie: Novinky z projektov

Certificate update - please update old BOINC clients

Einstein@Home - Pi, 13.04.2018 - 12:51

Due to Google removing trust for Symantec certificates, we need to update our SSL certificate. This will happen on Monday (Apr 16). The new certificate will ensure compatibility with new webbrowsers, but BOINC clients older than v7.4 may no longer be able to connect. If at all possible, please update your BOINC client.

read more

Kategórie: Novinky z projektov

Thanks for supporting SixTrack at LHC@Home and updates

LHC@home - Ut, 23.01.2018 - 19:08
Dear volunteers,

All members of the SixTrack team would like to thank each of you for supporting our project at LHC@Home. The last weeks saw a significant increase in work load, and your constant help did not pause even during the Christmas holidays, which is something that we really appreciate!

As you know, we are interested in simulating the dynamics of the beam in ultra-relativistic storage rings, like the LHC. As in other fields of physics, the dynamics is complex, and it can be decomposed into a linear and a non-linear part. The former allows the expected performance of the machine to be at reach, whereas the latter might dramatically affect the stability of the circulating beam. While the former can be analysed with the computing power of a laptop, the latter requires BOINC, and hence you! In fact, we perform very large scans of parameter spaces to see how non-linearities affect the motion of beam particles in different regions of the beam phase space and for different values of key machine parameters. Our main observable is the dynamic aperture (DA), i.e. the boundary between stable, i.e. bounded, and unstable, i.e., unbounded, motion of particles.

The studies mainly target the LHC and its upgrade in luminosity, the so-called HL-LHC. Thanks to this new accelerator, by ~2035, the LHC will be able to deliver to experiments x10 more data than what is foreseen in the first 10/15y of operation of LHC in a comparable time. We are in full swing in designing the upgraded machine, and the present operation of the LHC is a unique occasion to benchmark our models and simulation results. The deep knowledge of the DA of the LHC is essential to properly tune the working point of the HL-LHC.

If you have crunched simulations named "workspace1_hl13_collision_scan_*" (Frederik), then you have helped us in mapping the effects of unavoidable magnetic errors expected from the new hardware of the HL-LHC on dynamic aperture, and identify the best working point of the machine and correction strategies. Tasks named like "w2_hllhc10_sqz700_Qinj_chr20_w2*" (Yuri) focus the attention onto the magnets responsible for squeezing the beams before colliding them; due to their prominent role, these magnets, very few in number, have such a big impact on the non-linear dynamics that the knobs controlling the linear part of the machine can offer relevant remedial strategies.

Many recent tasks are aimed at relating the beam lifetime to the dynamic aperture. The beam lifetime is a measured quantity that tells us how long the beams are going to stay in the machine, based on the current rate of losses. A theoretical model relating beam lifetime and dynamic aperture was developed; a large simulation campaign has started, to benchmark the model against plenty of measurements taken with the LHC in the past three years. One set of studies, named "w16_ats2017_b2_qp_0_ats2017_b2_QP_0_IOCT_0" (Pascal), considers as main source of non-linearities the unavoidable multipolar errors of the magnets, whereas tasks named as "LHC_2015*" (Javier) take into account the parasitic encounters nearby the collision points, i.e. the so called "long-range beam-beam effects".

One of our users (Ewen) is carrying out two studies thanks to your help. In 2017 DA was directly measured for the first time in the LHC at top energy, and nonlinear magnets on either side of ATLAS and CMS experiments were used to vary the DA. He wants to see how well the simulated DA compares to these measurements. The second study seeks to look systematically at how the time dependence of DA in simulation depends on the strength of linear transverse coupling, and the way it is generated in the machine. In fact, some previous simulations and measurements at injection energy have indicated that linear coupling between the horizontal and vertical planes can have a large impact on how the dynamic aperture evolves over time.

In all this, your help is fundamental, since you let us carry out the simulations and studies we are interested in, running the tasks we submit to BOINC. Hence, the warmest "thank you" to you all!
Happy crunching to everyone, and stay tuned!

Alessio and Massimo, for the LHC SixTrack team.
Kategórie: Novinky z projektov

LHC@home down-time due to system updates

LHC@home - Ut, 23.01.2018 - 11:19
Tomorrow Wednesday 24/1, the LHC@home servers will be unavailable for a short period while our storage backend is taken down for a system update.

Today, Tuesday 23/1, some of the Condor servers that handle CMS, LHCb and Theory tasks will be down for a while. Regarding the on-going issues with upload of files, please refer to this thread.

Thanks for your understanding and happy crunching!
Kategórie: Novinky z projektov
Syndikovať obsah