My first programming job was working in David's research group, helping transition Dasher (http://www.inference.phy.cam.ac.uk/dasher/) from a research project into one more generally useful for accessibility purposes. I still feel that that job was perhaps the most useful work I've ever done - I had the opportunity to write code that in some cases literally made it practical for people to communicate, and that (along with David's strong views on social responsibility) ended up strongly shaping my perspective on what technology's role in society should be.
I saw David only rarely after leaving the group to do my PhD, and hadn't in years before I saw him at a group reunion last month. I'm saddened that I passed on so many opportunities to learn more from him.
Regarding Dasher, David mentioned recently* that he hopes someone carries on supporting the work. It's a brilliant example of arithmetic coding in action and helps many people communicate through low bandwidth channels. Now that he's gone, I don't think any has any ownership over the project. It'll be a huge shame for it to be forgotten about. If anyone's interested in helping in someway, mention it here and I'm sure we can figure something out. Here's a quick example of it an action (https://youtu.be/ie9Se7FneXE?t=28m38s - Google Talk from 2007)
[*] David was still teaching us information theory just last month, despite going through chemo which by his admission seemed to take a lot out of him. By everyone's account he was astounding lecturer. He really cared that no one fell behind. Very sad about the news today.
A British scientist and mathematician known for two fine books, both of which are available to read online.
"Sustainable Energy - without the hot air" (http://www.withouthotair.com/) does the sums on sources of sustainable energy, to try to establish whether they present a realistic alternative to fossil fuels. It might make sense to read this as a companion to Bret Victor's "What can a technologist do about climate change?" (http://worrydream.com/ClimateChange/), though MacKay's book mostly doesn't talk about climate change but about fuel exhaustion.
"Information Theory, Inference, and Learning Algorithms" (http://www.inference.phy.cam.ac.uk/mackay/itila/) is a readable and charming (but mathematical) book that touches on a lot of topics in information theory. A lot of it is over my head, but I most recently referred to it just a couple of weeks ago for its chapters about the mathematics of neural nets, including a chapter given to estimating the information capacity of a single neuron.
I know him from his pioneering work on sustainable energy. Actually working out from physics principles what is possible that can balance supply and demand in an ongoing way.
You can read it free online - I like the print copy though! (It's for the UK, but has lots of useful referenced data for anywhere)
I met him a few times in Cambridge trying to organise a campaign about Climate Change. He was passionate and fun. Sad that I never really delivered for him.
Rest well David, combining a scientist's accuracy and detail with a human's care for the world.
I saw him present the material from Sustainable Energy Without the Hot Air at a lecture in Cambridge. It remains the best lecture I ever saw. He crammed months' worth of learning into my brain in an hour. And he invented Dasher. Top bloke.
This is deeply saddening, and a huge loss for rational thought at the highest level. With his book on information theory and learning algorithms, David leaves the wonderful legacy of demystifying the central concepts that have brought about the ongoing information revolution, and it remains an absolute tour-de-force, even after years of further developments. I want to say "thank you" for all the wonderful insights; presented with clarity, wit and humanity.
David J. C. MacKay (born 1967-2016), British academic researcher in information theory and environmentalism, inventor, government advisor and educator:
His lectures on inference were the best and most worthwhile course I took as an undergraduate, and his text book is good enough that I have two copies at home and one at work. He had a big effect on how I look at the universe. He later became one of the only voices on energy policy that I trusted, and enjoyed hearing his clear thinking on the national news. Thank you, djcm. The world owes you quite a lot and probably has yet to realise it.
A professor of mine instructed me to "devour" MacKay's "Information Theory, Inference, and Learning Algorithms". To this day it is one of the only textbooks I have purchased on my own initiative (not for a class), and this is after I read many chapters online. I also thoroughly enjoyed his video lectures [1] for a course he taught based on the book.
His book, renewable energy without the hot air, is something that I frequently use as a reference and my last comment on Hacker news was a reference it. I had no idea he had cancer, as I read his other blog.
It's deeply saddening that someone who has had a significant positive impact on the UK - as an advisor to the government - and world, won't be able to continue to make more positive impacts. I imagine it would be hard for someone to fill the gap that has been left by him.
One hell of a great communicator. Large swaths of my life are still affected by his Sustainable Energy book. I never had a chance to meet him, but I'll carry his words with me forever.
His lectures as part of the Physics tripos were certainly the best (in terms of engaging, exciting, interesting and actually educating) I remember as an undergrad - at the time the smartness, enthusiasm and slightly unorthodox approach reminded me a bit of what I'd imagine Feynman's teaching to have been like.
It's a huge testament that right now now I can see 3 different copies of Information Theory, Inference, and Learning Algorithms sitting on 3 different desks in our office. He will be missed :(
I saw David only rarely after leaving the group to do my PhD, and hadn't in years before I saw him at a group reunion last month. I'm saddened that I passed on so many opportunities to learn more from him.