Thursday, November 16, 2006

The Rabin Ezra Scholarship Trust

Rabin's web site now includes a link to the Scholarship Trust. This has established a fund for graduate students in computer science (particular computer graphics and associated areas). Full details are available on the web site.

Monday, October 02, 2006

Rabin and me at Manor Junior School – 1974 - 1978

Rabin and I were at Manor Junior School together for 4 years, between the ages of 7 and 11. During this time Rabin was my closest friend. I actually appear in the photo of Rabin’s 7th birthday on the website (the photo on the far right, third row up).

Our first year teacher at Manor was Miss Thomas, a Welsh lady with red hair and a rather shaky grasp of spelling. In the second year, we had the truly scary Miss Blunden – if two children were sent by another teacher to give her a message, she would ask them why it took two of them to deliver the message – yes, that scary. In the third year we had the gentle Miss Hawton and then in our last year the beautiful but forbidding Mrs Harvey (nee Murphy – or Mrs Murphy, nee Harvey, I can’t recall which, now). For an unfashionable London suburb Barking had some fairly exotic inhabitants at this time. There were children from the Indian sub-continent, China, sub-Saharan Africa and the Caribbean at the school. There were also the children of people who had fled the Vietnamese war and its aftermath – what were termed in the media at the time, the ‘Vietnamese Boat people’. But Rabin seemed to me to be truly global. My geography was rather sketchy at the time, but I was aware of an Indian connection, a Middle Eastern link and an association with America.

Rabin himself was without a doubt unique. My abiding impression of him is that he was very serious. But looking at all the photos on the website he is always smiling, so I think it was probably just that he was seriously clever. We would spend hours together after school or during the holidays either in my garden shed, our bedrooms or his conservatory at 35 Edgefield Avenue. We didn’t play so much as ‘work on projects’ – hare-brained schemes usually thought up by me (the fantasist) which would then have to be implemented as far as was possible given our limited resources by Rabin (the genuine child prodigy). A working car which we could tour the world in built entirely out of Meccano; a rocket to send our Action Men into space, and so on. Rabin would spend most of these sessions instructing me in the art of the possible and coming up with workable alternatives to satisfy my childish imagination – so the Meccano car became a small but very serviceable crane; the space rocket a helicopter back-pack for an Action Man using a small electric motor etc. In fact electric motors and circuits with light-bulbs formed a very important part of our relationship for a period, which is not as odd as it sounds for two 8 year old boys.

Occasionally we would take a break from our scientific endeavours and I would coach Rabin at football, this being a suitable trade for the hard science that he imparted to me. Rabin was the first person to tell me about things like the Theory of Relativity and quantum mechanics. Even at this young age he seemed really to understand these things: I just marveled at them, and at him for knowing about them. The other thing that interrupted our important and ground-breaking work on Action Man propulsion systems, was the marvelous food made by Rabin’s Mum. I remember Rabin’s Mum having the most delightful smile and a lovely gentle nature which I think Rabin inherited from her.

Even Rabin’s bedroom was unique. His endlessly inventive Dad, whom I revered as a sort of suburban Carl Sagan, had suspended his bed from the ceiling with metal pipes, to give him more room. This was for us an incredibly exciting development which I never tired of seeing. Rabin’s Dad had done all sorts of interesting things in his life. One that stuck in my memory was that whilst in Canada* he had driven several different cars during a single day. I can’t remember why, or what job had involved this feat, but I was extremely impressed by it.

The scope of Rabin’s knowledge was certainly not confined to the natural sciences. He also had insights in fields such as psychology. I remember him confiding to me that he thought one of our rather highly strung schoolmates was probably suffering from a psychological disorder. I can’t recall what exactly his diagnosis was, but it was the first time it had occurred to me that people can break down too.

I was interested, but not at all surprised, to hear that Rabin had mastered Japanese. I recall an early example of Rabin’s analytical approach to language. There’s a road in Barking called Beccles Drive – pronounced ‘Beckals’, like ‘Eccles’ cake. One day walking back from school he challenged the accepted pronunciation saying that as it had a double ‘C’ it should be pronounced ‘Beck-les’. I wasn’t sure, but Rabin was quite adamant. I think in this instance Rabin may have got a little carried away by his own logic (it’s definitely pronounced like ‘Eccles’!), but it is an example of him analyzing and challenging received views at a very young age.

The other area of occasional collaboration between us was in the field of music. Rabin played the violin and I played the trumpet. Rabin played in the string orchestras conducted by the peripatetic teacher, Mr Stuckey. Anyone who has ever heard a Junior School string orchestra (and I understand that they are much rarer now than they used to be) will be acquainted with the fact that young children generally don’t have the motor skills required to produce a truly musical effect on string instruments (I think this is a charitable as I can be on this). Any fool can blow into a trumpet. But to tease a rich, sustained note out of a violin or cello requires a real touch which kids just don’t have. Rabin, as I recall, actually played very well, but as a rule, the string orchestras produced a rather thin, reedy sound. Not to worry though, because Mr Stuckey would compensate by humming the melody over the top of the orchestra – the perfect solution! For the finale of our summer school concert the senior string orchestra would be joined by the senior choir and part of the brass band to form a kind of super-group (think Bayreuth meets the Minipops!). I remember in our final concert together we played the Ode to Joy from Beethoven’s 9th Symphony. Coming as it did at the end of the summer term of our last year at Manor, this was probably the last thing that Rabin and I collaborated on.

All-in-all I doubt whether I made as lasting an impression on Rabin as he left on me, except perhaps in one respect. Some of you may have noticed that Rabin had a slight scar on his top lip – just to the right of centre. I see from the photos on the website that it was still visible when he was an adult. That, I’m afraid, was me. We were kicking a Coke can to each other in the street outside Manor Junior School after school one day in summer. I kicked it a bit too hard, and the coke can hit the edge of a paving stone and reared up hitting Rabin on the lip and giving him quite a deep cut. I always felt guilty about this. Rabin was a very gentle person, not naturally aggressive in the way that you need to be to be competitive in sports. By contrast, I was quite competitive and I think on this occasion I had kicked the tin can as hard as I could to put it past him. I hope the scar didn’t give him trouble shaving in later life.

Kids create their own worlds with a large measure of imagination and perhaps aren’t the most reliable witnesses. But this is how I remember it. I’m sorry I missed the opportunity to compare notes with Rabin – he might have remembered it more clearly. He made a greater impression on me than these few reminiscences can convey and I will always remember him.

Jonathan Fletcher

*Note from Rabin’s father - Rabin’s father was teaching in Canada. His class wanted to visit the Science Fair in Toronto. To raise funds for the visit a car ‘Washaton’ was organized. The teacher, Rabin’s father, was the only one allowed to move the cars – this was approximately 120 vehicles of various descriptions – all this in one day.

Friday, June 23, 2006

Random collisions

It’s strange, but back in the early ‘90s when I was a student at QMW if someone had pointed out to me the people I would consider friends in 2005, I probably would have been quite surprised.

I arrived at QMW in 1990, from small town Scotland, to do an MSc in the computer science department and my first memory of Rabin is of an enigmatic figure bobbing about in the labs in the ITL building wearing a fedora. I got to know that he was one of the notorious "ACE" lab people, a scary bunch interested in the details of computer graphics. As time went on and I became more of a fixture in the department myself, I joined in on some of the "departmental walks". It turned out that Rabin went on these too and I began to get to know him a bit better. He became known as "Teflon man" as no matter what state the rest of us were in, Rabin never had a speck of dirt on him. I also came to know that he drove very, very fast! Walks led to cycles and Rabin took part in these too…thrashing around the backroads of Kent.

Then there were the numerous evenings spent in the luxurious SCR bar, talking total rubbish…well, some of us talked rubbish, I don’t think Rabin ever did. It was there that I began to find out about Rabin’s incredible depth and breadth of knowledge. He could bring a drunken debate to a halt with one incisive statement of fact. I also began to find out that Rabin loved food, another common interest. He became renowned for ordering the weirdest thing on the menu…and actually eating it (and usually insisting that everyone else did too).

Anyway, we all left QMW (eventually) to do our various things. However, we still met up fairly frequently for beer and food and more drunken debate, we still do. For some reason I still hang on to the last email I have from Rabin suggesting a night out...

The last time I saw Rabin was in my own home, he was telling us that our imported Japanese beer wasn’t actually brewed there. Although it said "brewed in the Czech Republic" on the bottle, I’m pretty sure Rabin could really tell just from the taste.

I never heard Rabin say a word in anger, he could be animated, frustrated maybe, but never angry. His dry wit was also legendary as were his kindness and generosity. I wouldn’t claim that I knew him well, there were aspects of him that I really still know nothing about…his opinions on religion or politics for instance. However, I was always finding out more about him, what he was into, discovering common interests along the way. I would've enjoyed finding out more.

Perhaps the most amazing thing I’ve found out about him is that he and I share a birthday.

I miss him but I’m really glad that our worlds collided.

Saturday, November 19, 2005

Apocryphal Story?

I heard this story about Rabin a couple of years after he and then I left QMW. Perhaps someone can tell me if its apocryphal or not, or perhaps it was someone other than Rabin? I never remembered to ask him about it. Either way its a lovely "hacker" story - where "hacker" should be read as "master of things to do with computers" rather than its other negative interpretation.

In 1993-1994, the main workstations that students used were SunOS boxes with 68020 processors. Rabin and the rest of us in the graphics group were always looking for faster processors to run our calculations on - this in the days when SGI workstations were still few and far between because they were so expensive. So where to find this extra compute power? The workstations were running jobs over night anyway and we had no time-sharing system in the department.

This was a common problem, but someone, Rabin perhaps, had discovered that there was a faster processor available - on the printer! The laser printer had a 68030 processor, and for a short time this was one of the fastest compute machines in the department. So someone was encoding their jobs as Postscript and sending them to the printer to "execute" - the output being printed on the piece of paper. So some print jobs were suspiciously taking a very long time to come out!

Perhaps someone who knew Rabin better at the time can correct this - I only really knew him well after we had left QMW. In case anyone think this story a bit too unlikely, take a look at this URL - a working raytracer you can send to your Postscript printer.

Postscript Raytracer

Monday, August 22, 2005

Rabin's PhD

I first met Rabin Ezra some time in the second half of the 1980s. I taught the Computer Graphics course, a final year course at Queen Mary and Westfield College, Department of Computer Science. At that time the lab sessions were in an area of the college called ‘Stern Hall’. I had a lab class in there, and a young student approached me, someone I’d not seen before. He explained that he was an undergraduate in the Electrical Engineering Department and wanted to study the Computer Graphics course in the next academic year. After checking that he had the required knowledge of computer programming, I agreed. He seemed to be a very interesting student, and very interested in computer graphics, with also a good prior background that would enable him to do the course.

During the course itself I had several after-class discussions with him, and it was during one of these that the issue of his staying on to do a PhD arose. He was very interested in hardware for real-time computer graphics. Also I had read a very interesting paper by some people at Sun Microsystems that provided a very efficient method for the rendering of curves and surface that would be amenable to hardware implementation. Rabin became interested in this and we agreed upon this as his topic. He started the PhD probably in 1988.

He made rapid progress and actually soon had a hardware design for the main part of the surface generation graphics hardware. He passed his first and second year vivas without trouble. But then he did run into trouble. It seemed to be a trivial problem. Suppose you are given n points in 3D space. You need to decide if all these points are approximately on a plane. Mathematically this is not difficult. Take any three of the points that are not themselves on a straight line, and from these find the equation of the plane that passes through them. Then for each of the remaining points find their distance from this plane, and if the maximum distance of all these points from the plane is less than a certain fixed and given tolerance, then we can say that ‘approximately’ (how approximate depends on the chosen tolerance) the points are flat, i.e., are on a plane. Mathematically this is trivial. Transforming it into an efficient and accurate computer program is less trivial. Fitting it into a hardware design architecture so that it doesn’t become a major bottleneck is very difficult. This is what occupied Rabin for the remainder of his PhD. Finding some workable solution to this problem took about 2 years.

In January 1991 I took sabbatical leave from QMW to take a Visiting Professorship at University of California Berkeley in the Computer Science Division of Electrical Engineering and Computer Science. There I also taught the Foundations of Computer Graphics course, and continued with my own research. I was in frequent email correspondence with Rabin about the progress of his PhD, at that time he was still stuck on the ‘points on a plane’ problem described above. Having such a problem is not a ‘bad’ thing for a PhD because it leads to research avenues far from those envisaged at the start of the PhD research, and we certainly did come across a number of very interesting papers and lines of investigation that we would not have found but for this problem. Meanwhile it was during this period that Rabin became fascinated also with the ‘systems’ aspects of computer science. The Computer Science Department at QMW had been one of the first (or possibly the first) to bring the Unix system to the UK, and there were a number of experts there in this operating system. Moreover there was an active ‘systems group’ of people who continually investigated aspects of this system and others, and who became very technically proficient in these systems. They became ‘gurus’. They would (following the Computer Science at QMW tradition) work long hours into the night doing ‘system’ things, learning, trying, testing, debugging, implementing, solving problems: became a breed apart. Rabin became part of this group, transformed into a guru. This also had a detrimental effect on his PhD progress – no doubt exacerbated by my physical absence.

I was offered additional semesters (this time paid) by Berkeley, and therefore took unpaid leave from QMW in January 1992 until the summer. (I nevertheless had taught all my QMW classes compressed into one term, in October-December 1990 for my 1991 sabbatical and in October-December 1991 for my 1992 unpaid leave – such had become the nature of sabbaticals). My time at Berkeley had been so productive and enjoyable that I was very happy to be going back there for a second time. (I have to say also that teaching at Berkeley was far more rewarding than teaching at QMW at that time, but I think that this is a cultural difference relating to differences in students between the US and the UK. In the UK at the end of a lecture the students who would come to speak to me – in the main – Rabin being an exception – would say “I didn’t understand anything” “This course is very hard” “Is this going to come up in the exam?” and so on. At Berkeley, at the end of the class many students would come to talk to me enthusiastically about the ideas presented in the class, give their own opinions, talk about similar things they were doing in their part-time jobs and so on. It was a great pleasure to talk with them. In this respect Rabin followed more closely the model of the Berkeley student than the QMW student).

During this period Rabin and I had agreed that he would begin writing his PhD. One day shortly after I had returned to Berkeley Rabin sent me an email: “I’ve finished!”. I was very surprised. A PhD thesis normally runs to about 150 pages. Had he written so much, with all the references and all the figures, in such a short time? I asked him to send me the thesis. Well what he had written was fine – but it was about 40 pages in length. He had succinctly stated the problem, and the solution and results, in as terse manner as possible. There was nothing at all wrong with it, except that it really was too terse. So over the next year or so we gradually got more and more flesh put on the bare bones of the thesis. It was somehow against Rabin’s nature to spell things out in detail. “It’s obvious” he would say, "why should I have to write about it?" Well, obvious to him, and to me, but to the examiners, and other readers? – not so obvious. Yes, things have to spelled out, in detail. Where does this equation come from? Why is this statement true? What reference do you have to back up this idea? With some resistance Rabin eventually saw the light. But in a way of course Rabin was right. He had stated the problem and given the solution and results. Really of course the rest is convention. This is how a PhD is supposed to look. To be awarded a PhD he had to learn to follow certain conventions. But … they are only conventions.

He finally submitted in late 1993 or early 1994. The thesis length was still quite short, but acceptable.

On the day of the viva he was extremely nervous, to the point of shaking visibly – Rabin was not one for formally speaking in public, and he would have to do a short presentation in front of the two examiners. I told the examiners about his state. One of whom was Dr Simon Arridge from University College London who said I should tell Rabin not to worry, everything was ok. This did seem to quieten his nerves somewhat, and although still visibly shaking when he did his presentation, he got through it well. In the ensuing viva period he relaxed and engaged in genuine discussion with the examiners, and nothing remarkable happened. He was awarded the PhD.

After the award of the PhD Rabin went to work for Canon Research Europe where he specialised in graphics hardware and software, and especially on the interface between the two. CRE was partially founded by an ex-QMW student, and a number of ex-QMW people eventually worked there.

I kept in touch with Rabin over the years, and in particular used to meet him annually at the SIGGRAPH meeting in the US. I will write more about this at a later time.

Rabin is unforgettable. Although I will never see him physically again, he is still around. Although he passed away before SIGGRAPH 2005, I believe that he was still there, and enjoyed it as usual. He lives on at least through our memories and in our hearts.

Thursday, August 18, 2005

A good friend

Rabin was part of a circle of my friends that met when we were all at Queen Mary College. At the time, in the late 1980's, he was an undergraduate and I was working in the Computer Science department. We discovered a common interest in Role Playing Games which, if you don't know, are a very social activity involving sitting around acting out a story together, often in a fantasy "Lord of the Rings" type environment but also sometimes in futuristic or contemporary settings. The game is really an excuse to get together over some drinks and food and have a good time. Rabin was a well-loved member of our group and his intelligence and wry sense of humour will never be forgotten.

In latter years, as we have got older and ever more busy, it has become more difficult to arrange to meet up as a large group. However Rabin always made the effort to come along, even if it was just a couple of us meeting for a drink, or the occasional barbecues some of us hold. Out of all my friends I think he was the most intelligent, ethical, and dependable. I won't forget him.

Paul Davison

Rabin Ezra

This blog is dedicated to the memory of Rabin Ezra. Here his family, friends and colleagues will post their recollections, memories, thoughts, reflections, so that he will live on, and so that more and more people will come to know him.