1) Message boards : Science : How does Universe@H's BHSpin application differ from the new project BlackHoles@H? (Message 5255)
Posted 24 Apr 2022 by bozz4science
Post:
I've recently seen a spike in activity on the website in late Marche/April. Seems like the conducted a lot of software development. RAM requirements stated in one of the recent news was ~3 GB per task and as such much less demanding than initially feared. This is taken from the website:
After a year spent rewriting the software behind BlackHoles@Home, we're seeing beautiful results. In short, the software seems to do what it needs to do, but I'm still running it through some trials.
Black Holes @ Home website

Unfortunately still no concrete roadmap / launch date. Looking forward to it
2) Message boards : Science : How does Universe@H's BHSpin application differ from the new project BlackHoles@H? (Message 4763)
Posted 13 Jul 2021 by bozz4science
Post:
They just postponed the estimated start of the project and pushed it back one quarter. The revised start date is now fall 2021.

Additionally, the project that was to my understanding affiliated with the West Virginia University, now changed its project's lead to the University of Idaho.
3) Message boards : Number crunching : High invalid rate of latest ULX run (Message 4730)
Posted 20 Jun 2021 by bozz4science
Post:
Thanks for the feedback. Much appreciated!
4) Message boards : Number crunching : High invalid rate of latest ULX run (Message 4727)
Posted 20 Jun 2021 by bozz4science
Post:
Almost half of my most recent finished tasks are invalid. A lot of the still in progress tasks have been aborted shortly thereafter. Any pointers to what caused this?

And btw, what is the rationale behind the BHSpin WU vs. ULX reward?
My Ryzen 3700 takes between 1,400 and 3,600 sec for a BH Spin task with 1,333.33 credits and between 1,000 and 1,600 sec for an ULX task for 100 credits. An invalid rate of ~ 50% for the 13X less rewarding task type is a little bit annoying.

Thx
5) Message boards : Science : How does Universe@H's BHSpin application differ from the new project BlackHoles@H? (Message 4713)
Posted 26 May 2021 by bozz4science
Post:
Very interesting insights, thanks Jim for sharing! Your explanation hints at both projects becoming complimentary. You are indeed right that they seem to be modelling real-word data. Good to know! Having skimmed their technical paper, I still don't understand quite a lot, but the modelling approach really seems to be demanding (although Laptops are mentioned on their website). Excited to see how well these nested (adaptive mesh refined) Cartesian coordinate systems will perform. To my understanding, you can model these BH collisions/spins with less detailed coordinates exploiting near-symmetries.

Upon further reading, it seems that the project will demand ~1.8 GB RAM per task. They state that by tuning certain parameters in their application (that I don't comprehend at all), the numerical error of this application can be reduced while increasing the required RAM. However this is just a preliminary ballpark number it seems and might be subject to future changes. In the end this app will use about 50 times less RAM to simulate these spins compared to the current standard procedure/application. - That will render my 32 GB on my 8 core machine a definite bottleneck.
6) Message boards : Science : How does Universe@H's BHSpin application differ from the new project BlackHoles@H? (Message 4709)
Posted 25 May 2021 by bozz4science
Post:
Would be highly interesting though to understand how they differ. Once the new projects sets up shop with a new URL and a message board, I will likely ask this question there as I am sure that their project team is aware of Universe@Home.

Probably will have to stack up on memory :)
7) Message boards : Science : How does Universe@H's BHSpin application differ from the new project BlackHoles@H? (Message 4702)
Posted 24 May 2021 by bozz4science
Post:
Recently, I came across this new project, which is currently still under development.
http://astro.phys.wvu.edu/bhathome/

This is the main scientific journal article linked at their website elaborating on the scientific modelling methodology.
https://arxiv.org/abs/1712.07658

Since January the team behind this project are currently actively developing the apps and are set to launch it as standalone BOINC project by August 2021. Does anyone with a deeper scientific understanding know the difference in the 2 applications. From what I understand they will also study black holes but use a new holistic approach with an efficient coordinate system. The website states however, that the application will only require a few GBs of memory and that sounds as this new project will set way higher application requirements as Universe's BH-Spin application.

Would love to discuss these two different project/application setups!







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