* Posts by Nick 26

9 posts • joined 16 Jun 2009

Google says its quantum computer is 100 million times faster than PC

Nick 26

Carefully chosen benchmark comparison

Classical simulated annealing is not a particularly good optimization technique which was acknowledged in the paper:

"It is often quipped that Simulated Annealing is only for the 'ignorant or desperate'."

There are much better classical optimization technique which would compare much more favourably but they used it because it was the closest analogue to quantum annealing.

Simulated annealing also doesn't do well with potential energy surface which contain deep, narrow wells where it can get trapped. Quantum annealing can tunnel very efficiently through them and so they chose a problem which suited it. From the paper:

"carefully crafted proof-of-principle problems with rugged energy landscapes that are dominated by large and tall barriers"

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'iOS 9 ate my mobile broadband plan'

Nick 26

Easy fix is to turn off mobile data for hungry apps

I was hitting my data limit before WiFi-assist.

I went with the strategy of turning off mobile data for every app I had installed.

I then turned it back on as and when I first needed it.

I haven't hit my data cap since, not even with WiFi-assist and haven't noticed any loss of functionality.

iOS gives you the information about how much data different apps are using right in the settings,

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Troll sues Apple for daring to plug headphones into iPhone

Nick 26

Not necessarily two sockets

Nathan Hobbes wrote: "Not to state the obvious, but this explicitly talks about having 2 separate sockets, one for handsfree (mic/headphones) and one just for headphones"

Claim 1 ends with "said input-output and output interfaces to be jointly employed for said first and second headsets where said first and second headsets being the same headset" which at a stretch capturess the single connector with a single headset option.

In that case the prior art would be a mobile phone which played music/radio before 2001.

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Climate was HOTTER in Roman, medieval times than now: Study

Nick 26
Pint

Vineyards in York (-ish)

Just to add another post about the irrelevancy of the Romans having vineyards in York, a vineyard is currently operating just down the road in Leeds:

http://www.englishwineproducers.com/leventhorpe.htm

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IBM US nuke-lab beast 'Sequoia' is top of the flops (petaflops, that is)

Nick 26

@ John Savard

"one thing that wasn't mentioned was latency - or single-thread performance. Not everything can be parallelized well."

If your problem doesn't parallelize well and single thread performance is your main concern then you would buy a different (and much cheaper) machine.

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Slovakian police chief quits over Dublin explosives run

Nick 26

Yes it was safe

The pilot was right.

RDX is very stable.

They could have used it to boil the water for the in-flight drinks because it burns rather than explodes (although it's not something I'd advocate trying).

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Top 500 supers - world yawns at petaflops

Nick 26

Re: F@H

Chris Simpson wrote:

"What about Folding@Home, Granted not one single computer but 5+ Petaflop"

What Folding@Home does is millions of slighty different small problems.

What a supercomputer does is one very large problem.

The difference is tolerance to latency.

The answer to one F@H problem is independent of the other problems and so it can be task farmed. If you're dealing with one big simulation then you need as fast as possible communication between all the CPUs otherwise you'll be waiting an eternity for your answer.

Let's say you want to do some molecular dynamics on a piece of material the size of a grain of salt. Just holding the coordinates and velocities of all the atoms would require about 10 petabytes of memory. The drive for larger simulations, smaller approximations and finer resolutions will continue to feed these machines although Amdahl's law and other software engineering problems are raising their heads.

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That Digital Britain report in full

Nick 26

FM

The reason they want to close down FM is so that they can flog the frequencies to mobile networks

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