cdshaw@alberta.UUCP (Chris Shaw) (03/28/88)
I must say I'm getting rather tired of coming across articles that ask simple questions. Seems to indicate that people are posting the question as soon as it comes to mind, as opposed to going to the library or bookshelf to get the appropriate book. So... why not create a new newsgroup.. comp.graphics.newuser... which would have a whole bunch of answers to the standard questions which come around again and again and again and again and again and again and again and again. So what do you think? Dumb idea? Criminally smart idea? Tell me. -- Chris Shaw cdshaw@alberta.UUCP (via watmath, ihnp4 or ubc-vision) University of Alberta CatchPhrase: Bogus as HELL !
garry@batcomputer.tn.cornell.edu (Garry Wiegand) (03/29/88)
In a recent article cdshaw@pembina.UUCP (Chris Shaw) wrote: >I must say I'm getting rather tired of coming across articles that ask simple >questions. Seems to indicate that people are posting the question as soon as >it comes to mind, as opposed to going to the library or bookshelf to get >the appropriate book... I think it's entirely appropriate for people to ask simple questions here (as long as somebody is still enjoying answering them.) Telling people to "go to the library" is often not very kind or helpful. This business we're in hasn't been around very long, and the reference works just aren't very solid yet. My own experience with the literature has been that: A) It's hard work to find stuff. As far as I know, the ACM computer literature index died some years ago. What I generally do when I have a new topic to research, and I want to find the fresh work, is to pull all the recent issues of all the relevant journals off the shelf and start thumbing through them. I hope to find a "related" article and then work the references back. Pretty tedious. B) Many elementary algorithms which you would think "of course" are written down and available actually aren't. Oftentimes there's bits and pieces of things scattered around all over, but no-one ever got around to putting it all together sensibly and coherently before everybody lost interest in the subject. The hidden-line/ hidden-surface literature, for example, is a mess. C) Often when you do find an algorithm, the author wrote it out in narrative English. It can be amazingly hard to figure out what in the world the person meant to say! (There's a certain value in this game to making your solution *appear* to be nice and simple & elegant :-(. It can be even harder to figure out whether it's worth figuring out - whether the paper in your hand actually has some major flaw or missing improvement. D) My experience has been that even the nicely pseudo-coded algorithms in the classics (Newman and Sproull, Rogers, etc) are sometimes not quite right and/or just plain wrong. For example, all but one of the RGB/HLS conversion algorithms I've ever seen choose a bad method, and then a *lot* of them proceed to add bugs to the bad method in the course of writing it up. [I don't want to be too harsh on the authors: it's really hard work to make a published detailed algorithm "perfect".] E) Finally, there's always some residual worth in rehashing "old" subjects - often they're "old" because people got bored with them, not because the "best" solution had actually been reached. For example, I recall there's a tweak you can do to Liang/Barsky (ie, parametric) clipping that makes it run a bit faster than the published version. And we've noticed that even old Bresenham's algorithm is *not* the absolute fastest way to fill a Bresenham line on some machines. The silliest things can still allow room for improvement. Thanks for letting me ramble. Please be kind to new (and old) readers asking simple questions? garry wiegand (garry@oak.cadif.cornell.edu - ARPA) (garry@crnlthry - BITNET)
geoff@desint.UUCP (Geoff Kuenning) (04/02/88)
In article <4219@batcomputer.tn.cornell.edu> garry@oak.cadif.cornell.edu
(Garry Wiegand) makes many excellent points for continuing the discussion of
"elementary" issues. Well said, Garry!
I'd like to add one thing to his points: "going to the library" is not
necessarily even a viable option for many people. Here in LA, for
example, one would think that there are lots of places to go for
graphics publications. However, important parts of UCLA's collection
only go back five years; USC has similar deficiencies. The best
graphics collection is apparently at UC Irvine; depending on where you
live, that can be a 2 to 3 hour drive from home. For someone who
doesn't live in a big city with lots of universities, I could imagine that
going to the library for graphics literature could even become a two-day
project.
--
Geoff Kuenning geoff@ITcorp.com {uunet,trwrb}!desint!geoffksbooth@watcgl.waterloo.edu (Kelly Booth) (04/04/88)
In article <1705@desint.UUCP> geoff@desint.UUCP (Geoff Kuenning) writes: >I'd like to add one thing to his points: "going to the library" is not >necessarily even a viable option for many people. Here in LA, for >example... Did you try the LA local ACM SIGGRAPH? Some of the locals (LA, Bay Area, NY, and New England) have been around for quite some time and have as members people who have been in graphics many years.
snyder@boreas.steinmetz (Snyder) (04/05/88)
In article <1705@desint.UUCP> geoff@desint.UUCP (Geoff Kuenning) writes: >I'd like to add one thing to his points: "going to the library" is not >necessarily even a viable option for many people. Here in LA, for >example, one would think that there are lots of places to go for >graphics publications. However, important parts of UCLA's collection >only go back five years; USC has similar deficiencies. The best >graphics collection is apparently at UC Irvine; depending on where you >live, that can be a 2 to 3 hour drive from home. For someone who >doesn't live in a big city with lots of universities, I could imagine that >going to the library for graphics literature could even become a two-day >project. >-- > Geoff Kuenning geoff@ITcorp.com {uunet,trwrb}!desint!geoff Ever hear of inter-library loans? I'm not from California, but many libraries here on the east coast will forward material, or in the case of journal articles, copies of the articles. If you can find a reference (most university libraries should be able to help you with a literature search also), and your library doesn't have the item, chances are they can get it for you. Some experience in the past is that this takes on the order of a week, maybe two. And you get the information first hand. Using news, it probably will also take a week, and you will either get second hand information or a reference to what you should have had anyway. I'm not against asking questions on the network. I think its good and one of the purposes of this newsgroup. But making some effort to find the answer to your question yourself is probably more beneficial to you and less annoying to the rest of the network. Derek Snyder
geoff@desint.UUCP (Geoff Kuenning) (04/09/88)
In article <10253@steinmetz.steinmetz.ge.com> snyder@boreas.UUCP (Derek Snyder) writes: > Ever hear of inter-library loans? I'm not from California, but many libraries > here on the east coast will forward material, or in the case of journal > articles, copies of the articles. If you can find a reference (most university > libraries should be able to help you with a literature search also), > and your library doesn't have the item, chances are they can get it for > you. As it happens, all of the libraries in the UC system, plus some others like USC, are tied together this way; there's even a computer database (I think it's called Euclid) for searching through all libraries at once. Using this, it is possible to locate all articles with certain keywords in the title, or by a certain author, plus subject-categorized searching. Assuming I live in a built-up area like LA (I do), the system then works like this: (1) Drive 45 minutes to UCLA (the nearest one for me), and use Euclid to look up the keywords I can think of. Pay $100-$200 for a library card (or, cheaper, enroll in any extension course and pay $8.75) on the spot, and order the 5-50 articles that the search discovers. (2) Wait about a week while these things show up. Of course, they won't show up all at once (some will be out), and the library won't hold them forever until you come to get them. So you will have to make 2-3 more trips to see what you ordered. (3) Of course, keywords and subject categorizations always miss a lot of stuff, as well as producing a lot of chaff. (The last time I researched something, my first search missed an *entire journal* devoted exclusively to the subject I was interested in.) So you will have to go through the references and develop a supplementary list of things to order. Often, this will be larger than the first. (4) Repeat steps 2-3 several times, resulting in a total of 5-10 trips to your not-so-nearby library, to get a comprehensive list of references on the subject. Each trip takes 1.5 hours of your time, not counting time spent in the library. (5) Decipher all the articles you collected. Many will be mere expansions on previous articles, saying "we assume the reader is familiar with the Foo algorithm and notation", so that you have to track down and read a 1965 article before you can figure out the thing you have isn't relevant. (6) Having selected a promising algorithm or algorithms, repeat steps 2-3 at least once more, this time getting all copies of the next year or two of the relevant journal after the article appeared, so you can search for corrigenda and letters entitled "A Note on the Foo Algorithm." Typically, these items aren't indexed, yet they are often of critical importance. (7) Now the fun begins. Implementing the algorithm can take weeks to months, depending on complexity and on how well the paper you selected describes it. Ever try to produce decent C code for a 1975 Fortran-specified algorithm? And that's the easy case; it's even more fun working with a paper translated from a foriegn language that never gave code in the first place. I know whereof I speak; I have researched more than one subject exhaustively, starting essentially from scratch. The subject I covered most thoroughly literally took me many months and occupied several hundred hours of my time. Given the difficulties of this (which are badly compounded if you aren't close to a good university library), is it surprising that people ask the net? A simple net broadcast has a good chance of reaching a person who makes a specialty of the field you are investigating; that person often can point you directly at the 2 or 3 really important works on the subject. An example is compression: there are probably 50 papers in the field, but all you really need to read is Lempel-Ziv. Furthermore, there is a good chance that you will discover somebody who has working code and is willing to send it to you. > But making some effort to find > the answer to your question yourself is probably more beneficial to you > and less annoying to the rest of the network. Depends on whether you want to know about the subject, or just working code. If I plan a PhD thesis on the subject, I'd agree. But if the problem is incidental to my main goals, I'm interested in a solution, and the quickest way is often the net. -- Geoff Kuenning geoff@ITcorp.com {uunet,trwrb}!desint!geoff