petschge

46 ms·

211.
by petschge 6y ago
Nothing limits the field of critics to people who have written their own code and know what they are doing.
212.
by petschge 6y ago
It really helps with debugging if your MC code is deterministic for a given input seed. And then you just run for a sufficient number of different seeds to sample the probability space.
213.
by petschge 6y ago
One example: My code used to crash for a long time if you set the thermal speed to something greater than the speed if light. Should the code crash? No. And by now I have found the time to write extra code to catch the error and midly insul
214.
by petschge 6y ago
Be very careful grinding, polishing or otherwise ablating any alloy that contains beryllium. Berylliosis (no matter if acute or cronic) is no joke.
215.
by petschge 6y ago
There is more macroscopic variables, for example the three components of the bulk flow velocity or the density of the gas.
216.
by petschge 6y ago
DSL might only be 1.5 Mbps where you are but it is standardized between (at least) 0.7Mbps and 300 Mbps. I personally have used it at speeds between 2 and 100 Mbps.
217.
by petschge 6y ago
There is things such as SPARC by Commonwealth Fusion Systems (CFS) using rare-earth barium copper oxide (REBCO) superconductors. Not quite the scale of ITER, but it should give us some first experience working with that material. If that wo
218.
by petschge 6y ago
To get fusion there is a couple of ways: There is gravitational confinement (that is how stars do it, but it is impractically large for humans), there is inertial confinement (get enough energy out before it explodes, but that only works fo
219.
by petschge 6y ago
Yes that has a big impact. The quality of a tokamak (as meassured by the triple product density, temperature, and confinement time) goes up like B^3 (IF I remember correctly, I do plasma physics but not fusion stuff) and the fussion power g
220.
by petschge 6y ago
The characteristic frequencies in the plasma are much higher. Kilohertz and up. The steady state will be reached within seconds, so to the plasma 8 minutes is basically "infinity". But at that point the all the power that is leaki
221.
by petschge 6y ago
The simple answer is that the surface only goes up a factor of 4 if you increase the radius by a factor of 2, but the volume goes up by a factor of 8. So the ratio of (energy containing) volume to surface (where energy get's lost) if g
222.
by petschge 6y ago
LaTeX is a bit like democracy. It is horrible, but all the alternatives I have tried a worse.
223.
by petschge 6y ago
Recently bought T490 worked with Debian stable out of the box.
224.
by petschge 6y ago
I have a X1 Carbon that is a few years old now. About 2 years ago I dropped it (lid closed) from about 2 feet up (70cm). And it hit the tiled floor, pointy corner first. I thought "welp here go $2000". But no! A 2x3 mm part of the
225.
by petschge 6y ago
There is a massive working medium. For massless particles such as photons the connection between energy E and momentum p is E = p *c or p = E/c. Since c is large, the momentum p you can carry per energy E is small. For a massive partic
226.
by petschge 6y ago
Expressing all quantities as small multiples of suitable reference quantities is quite common. The resulting equations after simplifications are often referred to as dimensionless (because the reference quantity has absorbed the units and o
227.
by petschge 6y ago
Actually we can detect them, thanks to the Stereo satellites. (And also indirectly through helioseismology.)
228.
by petschge 6y ago
Technical conferences switch to videoconferencing software. But they got much much worse in the process.
229.
by petschge 6y ago
As the old quip goes: A real computer scientist would not work with anything less portable than a #2 pencil. And at the risk of explaining a joke that applies to both the weight and the applicability of the results to ALL computers.
230.
by petschge 7y ago
In data that are 2 days to 5 weeks old we see that it kills as many as a bad flue year despite massive efforts to contain it.
231.
by petschge 7y ago
Both Munich and Prague have started such studies with several thousand random people in each. That should give us a much better estimate for the number of "silent" cases.
232.
by petschge 7y ago
I know that Glasser and Qin at Princeton are working on geometrical view of plasma physik. They aim to get a view of particle-in-cell methods (basically a way to discretize the Vlasov equation using sparse sampling) using a geometric view p
233.
by petschge 7y ago
Not really. The majority of cases of the common cold are caused by rhinoviruses, not coronaviruses. Then again I would gladly take a 10% cut in the common cold...
234.
by petschge 7y ago
I was at a conference last week that got partially converted to video-conferencing because NASA people were not allowed to attend. And as much as flying to conferences sucks I can say with 100% certainty: web-interaction is hilariously far
235.
by petschge 7y ago
How about instead of simply getting bailed out they have to create additional shares that they sell to the government at the current price set by the open market. The government is then free to sell the shares after some time or to actually
236.
by petschge 7y ago
You do need testing to dial in what level of social distancing brings the rate down to a level the health care system can handle without dragging out the crisis needlessly long.
237.
by petschge 7y ago
Completely solved problem? What about lab courses?
238.
by petschge 7y ago
Because nothing is set up for it yet. There is a reserved scheduled class room for the class, but there is no organized zoom meeting yet (or maybe not use zoom after all?). There is a mail box to drop of home work assignments, but nobody ha
239.
by petschge 7y ago
I am at a (small) academic meeting right now and all of the professors in attendance fear how much extra effort this move to online-only classes will be and how it is going to cut into their research time.
240.
by petschge 7y ago
Could you do the same with time after 500 (or 1000) cases. There is a whole bunch of parallel curves that seem to be displaced mostly because of differences in early testing but otherwise show the same growth rate.

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