4 ms·

Oh yes. I've a book on dynamic programming (Applied Dynamic Programming, Bellman + Dreyfus, seriously over my head unfortunately) which uses missionaries, canni

Oh yes. I've a book on dynamic programming (Applied Dynamic Programming, Bellman + Dreyfus, seriously over my head unfortunately) which uses missionaries, cannibals and a boat to cross a river (page 97). The authors talk about M cannibals and N missionaries. Note again: he used the letter M for cannibals, not the missionaries, which I note start with that letter. And he could have called the cannibals C but, no. I literally can't understand what mental process led them to do this, or not realise. Another thing I detest is mathematician's fear of brackets. They'd rather use a tower of unstated precedences than just bracketing the fuckers. Fine, I suppose, if you know the subject but I was trying to learn something recently, something with quantifiers and implications nested densely, and was left mentally bracketing the various subexpressions to (try to!) work out what was meant. If I have to fight the syntax I'm already being blocked from understanding the semantics. Mathematicians really do make things hard sometimes. Thankfully us programmers are so much better (sarc)

jerf 8y ago
Ah yes, you reminded me. There was another piece of jargon I was trying to come up with that really stinks earlier, but I couldn't remember it. And that's what it was: dynamic programming. Terrible name: "Where did the name, dynamic programming, come from? The 1950s were not good years for mathematical research. We had a very interesting gentleman in Washington named Wilson. He was Secretary of Defense, and he actually had a pathological fear and hatred of the word research. I’m not using the term lightly; I’m using it precisely. His face would suffuse, he would turn red, and he would get violent if people used the term research in his presence. You can imagine how he felt, then, about the term mathematical. The RAND Corporation was employed by the Air Force, and the Air Force had Wilson as its boss, essentially. Hence, I felt I had to do something to shield Wilson and the Air Force from the fact that I was really doing mathematics inside the RAND Corporation. What title, what name, could I choose? In the first place I was interested in planning, in decision making, in thinking. But planning, is not a good word for various reasons. I decided therefore to use the word “programming”. I wanted to get across the idea that this was dynamic, this was multistage, this was time-varying. I thought, let's kill two birds with one stone. Let's take a word that has an absolutely precise meaning, namely dynamic, in the classical physical sense. It also has a very interesting property as an adjective, and that is it's impossible to use the word dynamic in a pejorative sense. Try thinking of some combination that will possibly give it a pejorative meaning. It's impossible. Thus, I thought dynamic programming was a good name. It was something not even a Congressman could object to." - https://en.wikipedia.org/wiki/Dynamic_programming#History https://en.wikipedia.org/wiki/Dynamic_programming#History A Congressman may not be able to object, but I do! It's a particular flavor of recursion, and perhaps a flavor of the term "recursion" would be called for, but "dynamic programming" is essentially meaningless. Any addition meaning that phrase may have in your head is almost certainly unrelated to what the term refers to, since we've used "static" and "dynamic" in all sorts of ways since the 1950s.
- tempguy9999 8y ago
  Heh. That quote is from Richard Bellman. Same guy who was one of the authors of that book I'm criticising. But please allow me to disagree with you. The term programming/programme predate programming as we know it, and he was free to use it in the sense of 'scheduling', much like a radio or TV schedule. The dynamic also makes sense as the schedule (or whatever) picks its next state depending on a previous/simpler state (hence a 'stage' in multistage, though I can't understand his use of 'time-varying' here). I think it's ok. I'd rather punch mathematicians who won't bracket over mathematicians who try and protect themselves and their work from over-powerful, deeply stupid people.
weinzierl 8y ago
i, j, k, l, m ,n suggest that this problem is concerned with an integral number of cannibals and missionaries. Usually these letters are assigned in the order of occurrence. If cannibals were introduced first and missionaries second it would be unnatural to assign missionaries an m. Further a c for cannibals would be counter-intuitive because c is often used for constants. > Mathematicians really do make things hard sometimes. Hard for non-mathematicians for sure, hard for themselves often enough too; but not this time.
- tempguy9999 8y ago
  1, 2, 3... have a natural ordering. a, b, c...i, j, k...z do not. Alphabetical ordering is convention and no more than that. To say, let's apply this convention to a problem to which such an ordering has literally no relevance, and ignore their value as a mnemonic, is bizarre beyond my comprehension. I suspect some ultra smart people like Bellman, and possibly you, can attach completely arbitrary labels to things and immediately use those. I suspect that's what happened here. But I can't, and I'm pretty sure most people can't. To us, it helps greatly if the label has some relationship to the thing labelled

jerf 8y ago

Ah yes, you reminded me. There was another piece of jargon I was trying to come up with that really stinks earlier, but I couldn't remember it. And that's what it was: dynamic programming. Terrible name: "Where did the name, dynamic programming, come from? The 1950s were not good years for mathematical research. We had a very interesting gentleman in Washington named Wilson. He was Secretary of Defense, and he actually had a pathological fear and hatred of the word research. I’m not using the term lightly; I’m using it precisely. His face would suffuse, he would turn red, and he would get violent if people used the term research in his presence. You can imagine how he felt, then, about the term mathematical. The RAND Corporation was employed by the Air Force, and the Air Force had Wilson as its boss, essentially. Hence, I felt I had to do something to shield Wilson and the Air Force from the fact that I was really doing mathematics inside the RAND Corporation. What title, what name, could I choose? In the first place I was interested in planning, in decision making, in thinking. But planning, is not a good word for various reasons. I decided therefore to use the word “programming”. I wanted to get across the idea that this was dynamic, this was multistage, this was time-varying. I thought, let's kill two birds with one stone. Let's take a word that has an absolutely precise meaning, namely dynamic, in the classical physical sense. It also has a very interesting property as an adjective, and that is it's impossible to use the word dynamic in a pejorative sense. Try thinking of some combination that will possibly give it a pejorative meaning. It's impossible. Thus, I thought dynamic programming was a good name. It was something not even a Congressman could object to." - https://en.wikipedia.org/wiki/Dynamic_programming#History https://en.wikipedia.org/wiki/Dynamic_programming#History A Congressman may not be able to object, but I do! It's a particular flavor of recursion, and perhaps a flavor of the term "recursion" would be called for, but "dynamic programming" is essentially meaningless. Any addition meaning that phrase may have in your head is almost certainly unrelated to what the term refers to, since we've used "static" and "dynamic" in all sorts of ways since the 1950s.

tempguy9999 8y ago
Heh. That quote is from Richard Bellman. Same guy who was one of the authors of that book I'm criticising. But please allow me to disagree with you. The term programming/programme predate programming as we know it, and he was free to use it in the sense of 'scheduling', much like a radio or TV schedule. The dynamic also makes sense as the schedule (or whatever) picks its next state depending on a previous/simpler state (hence a 'stage' in multistage, though I can't understand his use of 'time-varying' here). I think it's ok. I'd rather punch mathematicians who won't bracket over mathematicians who try and protect themselves and their work from over-powerful, deeply stupid people.

weinzierl 8y ago

i, j, k, l, m ,n suggest that this problem is concerned with an integral number of cannibals and missionaries. Usually these letters are assigned in the order of occurrence. If cannibals were introduced first and missionaries second it would be unnatural to assign missionaries an m. Further a c for cannibals would be counter-intuitive because c is often used for constants. > Mathematicians really do make things hard sometimes. Hard for non-mathematicians for sure, hard for themselves often enough too; but not this time.

tempguy9999 8y ago
1, 2, 3... have a natural ordering. a, b, c...i, j, k...z do not. Alphabetical ordering is convention and no more than that. To say, let's apply this convention to a problem to which such an ordering has literally no relevance, and ignore their value as a mnemonic, is bizarre beyond my comprehension. I suspect some ultra smart people like Bellman, and possibly you, can attach completely arbitrary labels to things and immediately use those. I suspect that's what happened here. But I can't, and I'm pretty sure most people can't. To us, it helps greatly if the label has some relationship to the thing labelled