Skip to main content

Once upon and Algorithm - Martin Erwig ***

I've been itching to start reading this book for some time, as the premise was so intriguing - to inform the reader about computer science and algorithms using stories as analogies to understand the process.

This is exactly what Martin Erwig does, starting (as the cover suggests) with Hansel and Gretel, and then bringing in Sherlock Holmes (and particularly The Hound of the Baskervilles), Indiana Jones, the song 'Over the Rainbow' (more on that in a moment), Groundhog Day, Back to the Future and Harry Potter.

The idea is to show how some aspect of the story - in the case of Hansel and Gretel, laying a trail of stones/breadcrumbs, then attempting to follow them home - can be seen as a kind of algorithm or computation and gradually adding in computing standards, such as searching, queues and lists, loops, recursion and more.

This really would have been a brilliant book if Erwig had got himself a co-author who knew how to write for the public, but sadly the style is mostly heavy academic, so the cleverness is rather wasted. Sometimes this comes across in labouring points and at others in spending a lot of effort on what is little more than defining labels for things, rather than providing useful information and context for the reader. It's not that there's not a lot of good material in there, just that it's hard work to dig it out, where I'm sure the whole idea of using the stories was to make it more approachable.

Part of the problem is that the stories themselves don't always work very well as an analogy for what's happening in the computation. So, for example, in the section dealing with sorting he comes up with the task of sorting the tasks and places that Indiana Jones needs to deal with to find the Lost Ark. The unsorted list includes the likes of: disc, sunbeam, Marion and Nepal. The algorithm used involves finding the 'smallest' element... which somehow we are supposed to instantly see is Nepal. Using numbers would not have been so well-linked to the story, but at least it would have made some sense to the reader.

Perhaps the low point is the section that uses a part of the song 'Over the Rainbow' (giving us a tenuous story connection to The Wizard of Oz) to examine language and meaning. If you aren't familiar with musical notation, I'm not sure it's a very helpful analogy... and if you are, some of the ways it's used (particular the assertion of what bars are for) doesn't entirely make sense.

I was a professional programmer for a number of years, but without a computer science background. So I was very familiar with how to do this stuff, but knew nothing of the theory behind it. As such, I found the content of the book really interesting - and the story idea should have made it doubly brilliant - but the execution meant that it didn't deliver anywhere near as well as it could have. Even so, there's a lot to savour, and it's definitely worth persevering to get a feel for why computer programs involve far more than just 'cutting code.'


Hardback:  

Kindle:  

Using these links earns us commission at no cost to you

Review by Brian Clegg

Comments

Popular posts from this blog

Patricia Fara - Four Way Interview

Patricia Fara lectures in the history of science at Cambridge University, where she is a Fellow of Clare College. She was the President of the British Society for the History of Science (2016-18) and her prize-winning book, Science: A Four Thousand Year History (OUP, 2009), has been translated into nine languages. An experienced public lecturer, Patricia Fara appears regularly in TV documentaries and radio programmes. She also contributes articles and reviews to many popular magazines and journals, including History Today, BBC History, New Scientist, Nature and the Times Literary SupplementHer new book is Erasmus Darwin.

Why history of science?
I read physics at university, but half-way through the course I realised that had been a big mistake. Although I relished the intellectual challenge, I was bored by the long hours spent lining up recalcitrant instruments in dusty laboratories. Why was nobody encouraging us to think about the big questions – What is gravity? Does quantum mechani…

The Idea of the Brain: Matthew Cobb *****

Matthew Cobb is one of those people that you can’t help but admire but also secretly hate just a little bit for being so awesome. He is professor for zoology at the University of Manchester with a sizable teaching load that he apparently masters with consummate skill. He’s a scientific researcher, who researches the sense of smell of fruit fly maggots; I kid you not!  He’s also an attentive and loving family father but he still finds time and energy to write brilliant history of science books, three to date. His first, The Egg and Sperm Race, describes the search for the secret of human reproduction in the seventeenth and eighteenth centuries and is one of my favourite history of science books, on the period. His second, Life’s Greatest Secret is a monster, both in scope and detail, description of the hunt to decipher the structure and function of DNA that along the way demolishes a whole boatload of modern history of science myths. The most recent, and the subject of this review, is

The Search for Life on Mars - Elizabeth Howell and Nicholas Booth ***

From the book’s enticing subtitle, ‘The Greatest Scientific Detective Story of All Time’, I was expecting something rather different. I thought the authors would kick off by introducing the suspects (the various forms life might take on Mars, either now or in the past) and the kind of telltale traces they might leave, followed by a chronological account of the detectives (i.e. scientists) searching for those traces, ruling out certain suspects and focusing on others, turning up unexpected new clues, and so on. But the book is nothing like that. Continuing with the fiction analogy, this isn’t a novel so much as a collection of short stories – eleven self-contained chapters, each with its own set of protagonists, suspects and clues.

Some of the chapters work better than others. I found the first three – which despite their early placement cover NASA’s most recent Mars missions – the most irritating. For one thing, they unfold in a way that’s at odds with the cerebral ‘detective story’ na…