Personal Blogs

I was reminded of this today by a friend and colleague. The TSP problem asks how to calculate the shortest round trip between a set of cities, given the respective distances between them.

Simply comparing all the possible routes one after another will obviously work, but with even a few cities, and the fastest computer in existence, it could take thousands or millions or more years. So is there a way to solve it in a feasible length of time?

The TSP attracts a lot of attention, because it’s easily stated and most people have a gut feeling there should be a lightbulb intuition that will show the way. However decades of professional and amateur endeavour have not succeeded. We have good ways to calculate it well enough for delivery services say, but no way of finding the absolute optimum until the customer is long dead. Amazon and Google and others use algorithms which are good enough, and they are good enough; shaving 100 metres off a delivery trip will avail nought if there is a parked car en route. 

So it’s a theoretical question, but to my mind they are the ones that we learn most from.

Let XKCD have the last word. This is the approach that will probably work best in this year of crisis, and perhaps at all times.

https://xkcd.com/399/

I'm so glad dockers are exempt from quarantine rules. The're quay workers, after all.

Don't understand why piano tuners aren't available.They're key workers after all.

Found this scribbled on a napkin.

“This is how Swifty & Co. have always operated“, said Tom firmly.

Emperor “angered” as critics slam official response to burning of Rome

“We have done an exceptional job” Nero insists

Cat: May I order a mouse?

Waiter: Of course Sir. Would you like to see the mouse list?

Cat: No, I’ll just have the house mouse please.

What kind of feathers do you find on a lock?

Thermopylae

Honour to those who in the life they lead
define and guard a Thermopylae.
Never betraying what is right, 
consistent and just in all they do
but showing pity also, and compassion; 
generous when they are rich, and when they are poor, 
still generous in small ways, 
still helping as much as they can; 
always speaking the truth, 
yet without hating those who lie. 

And even more honour is due to them
when they foresee (as many do foresee) 
that in the end Ephialtis will make his appearance, 
that the Medes will break through after all. 

This poem is by Cavafy, one of the preeminent Greek poets of modern times. Thermopylae was the narrow pass where in 480 BCE Leonidas and his 500 Spartans held up the entire Persian invasion army long enough for the other Greeks to prepare their defence. Eventually they were outflanked when a local guide showed the Persians a mountain path that let them bypass the Spartan roadblock. Leonidas and the 500 famously refused to surrender and fought on to the last. When the Persian king Xerxes demanded they lay down their arms Leonidas is supposed to have answered “μολὼν λαβέ” - molon lave - “you come and get ‘em”.

There’s an interesting discussion of Cavafy and his work here

http://www.patrickcomerford.com/2013/11/reading-poems-of-cp-cavafy-in-greek.html

I don't know about real outlaws in the Old West, but the ones in films often wore a mask; typically a bananda, often fancy, that covered their mouth and nose. This was the badge that showed they were baddies. But could it really have prevented them being identified, the reason given for their wearing masks?

Probably, yes. I've just put on a surgical mask and tested my iPhone. It didn't recognise my face. Amazingly, the phone hadn't been confused in the least bit by my radical beard trim, done some weeks back, for reasons of hygiene. But this is different. My phone didn't know me any more. I could still tap in the passcode of course.

Not all Western outlaws wore bandanas; there was a second popular style: the black mask around the eyes, like Zorro or the Lone Ranger.

Whether Style 2 affects the iPhone facial recognition or not I don't know yet. My prediction is the impact will be less than for Style 1.  I've bought a Zorro mask online and will be able to report further, sometime towards the end of next week.