Here is a story in the Belfast Telegraph about my rather brave cousin Diane McCaughan showing cancer who is boss.
I have two phones, currently a Samsung Galaxy S5 for domestic use, and an iPhone 4S for work. I used to have an iPhone 4 for work but its radio functionality started sporadically not working. Actually it would be better to say it didn’t work and would sporadically work.
About a week ago, my 4S started the same behaviour, I thought an upgrade to iOS 8 might fix it, but of course it couldn’t download the update. So I used iTunes (which I really can’t stand) to do the upgrade.
It didn’t make any difference, in a few moments when radio functionality was working I was able to download some app updates, but generally nothing works reliably, or for more than a few seconds at a time.
(Of course iOS 8 does add some stuff – and it can’t be ignored it’s stuff that has been in Android for some time, the battery also started to drain at an unprecedented rate).
So I decided there was no choice but to do a reinstall of the phone. Grappling with iTunes again (grr) I get asked (again) if the computer is trusted, it is, it was, it still will be. I do a backup. I try to do a restore. But I can’t because it requires me to turn off “find my iPhone” in the iCloud settings. To do that, I need a working network connection through which to put my password (even though this is a trusted computer that has seen the phone before).
Nothing works, including trying to share my network connection through the iPhone USB.
So I consult the Oracale of Google, and find this is now an unknown problem, and that there is a procedure for putting the phone in a recovery mode (so what’s the point in the previous paranoia).
I do that, I reinstall the default firmware, and now can’t get a connection to verify the phone.
So, this is the second iPhone 4* I seem to have turned into a brick.
As you may have noticed, I have upgraded from Serendipity, which was creaking a bit, and seems to no longer be supported by Debian to WordPress. It was a moderately complex task, as I wanted to preserve backwards compatibility and a lot of content with mathematics and code.
I installed the Debian package, and tried to follow the instructions on the Debian wiki but they are perhaps out of date. I got an error trying to setup the database, but found it was there and functional.
IÂ then used this excellent script to help import the old serendipity data. It wasn’t without problems, the script needed to be placed (on the Debian installed package) under /var/lib/wordpress/wp-content/plugins/ within a directory to be registered by WordPress as a plugin, but I got that working in the end.
This was an attempt to preserve ID fields as well. It seems to have worked – which has simplified redirects (see below). Comments have been “flattened” as the script warned, and there’s clearly a character-set issue here and there, but these weren’t serious issues for me. Your mileage may vary.
I found a good plugin for GeHSI style code formatting which I was using in Serendipity, albeit the syntax is very slightly different so I have some work to do editing a few entries (I don’t want to attempt a global SQL regexp find and replace if I don’t have to). I found this excellent seeming plugin for Latex and switched it into site-wide mode. So far, checking a few old articles, it JustWorks (TM).
Some of my old posts have images in the serendipity media folders that will need moved, but I was keen to have links to the old blog redirect automatically. I was able to use
RedirectMatch permanent ^/serendipity/archives/([0-9]+).* http://www.piglets.org/blog/?p=$1
in my Serendipity Apache configuration to jump to the new articles.
I can start to dismantle the rest of serendipity, except for the media, quite soon now. It’s nice to have a platform that respects multiple device layouts, and hopefully comment spam will be easier to control too. A sample of most articles show they render OK, there are a few gotchas, and I’ll try to work through them in time.
Yesterday I was finally nominated for the Ice Bucket Challenge, I had actually thought this inevitable for the reasons in this post, but then it all kind of passed by. As it happens, it was my Daughter Aimee’s fault in the end. :-).
So I thought I would use the opportunity to bore people about the arithmetic behind it, in the end, I suspect that wasn’t too coherent since I was being watered at the time by my older Daughter Aimee, while my younger Daughter Matilda generally screamed at both of us.
So here is what I was trying to say. I like to talk to my students about a new version of an old problem. There’s an old story about a chess game where the winner will take away a certain amount of rice. The amount is calculated by having one grain on the first square, two on the next, four on the next, and so on, doubling all the way to the 64th square. My modified version is to consider coins, a UK 10 pence piece to be precise, piling up on the squares as we go along. The question is, how high is the pile of coins on the last square? I encourage you to guess, approximately what sort of size that is.
We double each time, so the number of coins on the first eight squares are 1, 2, 4, 8, 16, 32, 64, 128.
Another way to write that is
20, 21, 22, 23, 24, 25, 26, 27.
So, we are going along 64 squares, and start at 0, so the number of coins on the last square will be
263. This is a big number, but just how big? Do we change our guess on this information?
Now 263 â‰ˆ 9,223,000,000,000,000,000 = 9.223 Ã— 1018
and a ten pence piece is 1.85 mm thick, or 0.00185 m, so when we multiply these we get
17,063,000,000,000,000 m = 1.7063 Ã— 1016 m.
Wow. That seems like a lot. Just how big is that number as a distance?
To put it in perspective…
- by the 19th square, the coins are higher than the radio mast on the Empire State building;
- by the 29th square, the pile of coins would have reached the Moon;
- by the 48th square, the pile of coins would have reached the Sun;
- by the 63rd square, one from the end, the coins are a light year high.
This is an example of the staggering power of exponential growth, and just how unintuitive it is.
So what has this got to do with the Ice Bucket Challenge? Well suppose you start with a single individual, who then nominates three people, each of whom nominate three people. Now on the Chess Board we have 1, 3, 9, 27 and so on. This is, again, exponential growth with powers of three rather than two (actually somewhat higher growth).
Mathematically these are often called Geometric Progressions or just G.P.s for short. These are sequences of the type
a, ar, ar2, ar3, ar4, …
There is a formula that can be derived (it’s not hard, the derivation is on the above Wikipedia link) for the Sum of the first terms. (In Mathematics, contrary to popular opinion, a Sum specifically means the result of an addition process).
In the above case we can see that a = 1 because that’s the first number in 1, 3, 9, … and r = 3 because that is the number we are multiplying by each time. So here
In other words, every “generation” each person nominates a further three people, so the number of people added each generation ramps up exponentially, and the total number involved increased rapidly too.
|Generation||New People||Cumulative Total|
So you can see that after just 22 steps in the nomination process, you have literally more people than you have on the planet. Pyramid selling schemes become untenable for this reason too… you quickly run out of suckers on any given land mass.
So if this really ran its course unimpeded (and I know that the original challenge was money or dowsing, with a requirement to undertake the challenge in 48 hours (some say 24) then the whole planet would have done the challenge in at most six weeks. If each person had used say 4 litres of water then at the time of writing the 7,259,289,122 people alive today would have collectively used 29 billion litres of water. Since an Olympic swimming pool has 2.5 million litres of water, that represents over 11,614 swimming pools filled with water. While it is easy to criticise those who have been uneasy about the water wastage here, to be honest they have a good point. Also one organisation would have billions of charity income rather than it being spread.
Clearly this has not happened so people have run out on enthusiasm here and there. Anyway, have fun, and give some money to something you love, if you want, when you want to.
I am donating to
Since people I care about have been troubled by both, and
since it can’t be denied I live in extraordinary luxury to be able to waste perfectly good water on this kind of thing.