Geoff. Startling, and beautifully presented.
I had no idea ChatGPT was that powerful and knowledgeable. We are doomed. Craig > On Jan 20, 2023, at 8:05 AM, Alex Tweedly via use-livecode > <use-livecode@lists.runrev.com> wrote: > > Fascinating. Thank you so much for that Geoff. > > I've been afraid to play with ChatGPT so far - too worried abut getting > sucked in and spending way too much time .... > > I did take a look at your third example (since I can never resist a > performance challenge :-) > > There are a number of minor tweaks that could be made to improve performance > > 1. set initial value to infinity rather than calculating a distance between > the first two points. > > 2. "number of elements in pPoints" is unvarying within any one call - so > extract it to a variable at the start > > 3. use the square of the distance rather than the actual distance - save N**2 > calls to sqrt > > 4. use "DX * DX" rather than "DX ^ 2" (about 25% faster) > > 5. calculate distance in-line rather than call a function > > but those all add up to maybe 10% performance improvement (or less - I didn't > test it). That's useful - but not enough. > > For a modest number of points (2000 random points), this takes approx 16.5 > seconds !! > > We need a better algorithm. If we use a "linear scan", we can change it from > essentially Order(N**2) to approx Order(N). > > Summary: > > - sort the points by X coordinate > > - while scanning the inner loop, as soon as the difference in Xcoord from > the 'outer' point exceeds the minDist so far, you can reject not just this > point, but all subsequent points, and hence exit the inner loop immediately. > > This brings the time down from 16500 millisecs to 25 millisecs. > > BUT - I have no clue how I'd go about describing this to ChatGPT :-) > > NB I changed the input parameter to be the list of points rather than the > array. > > Code: > > function closestPointsSQ pLines > sort pLines by item 1 of each > put pLines into pPoints > split pPoints by CR > put infinity into minDist > put the number of elements in pPoints into N > repeat with i = 1 to N-1 > repeat with j = i + 1 to N > put item 1 of pPoints[j] - item 1 of pPoints[i] into t1 > if t1 * t1 > minDist then exit repeat > put item 2 of pPoints[j] - item 2 of pPoints[i] into t2 > put t1 * t1 + t2 * t2 into dist > if dist < minDist then > put dist into minDist > put pPoints[i] & " " & pPoints[j] into closestPoints > else if dist = minDist then > put return & pPoints[i] & " " & pPoints[j] after closestPoints > end if > end repeat > end repeat > return closestPoints > end closestPointsSQ > > -- Alex. > > On 20/01/2023 06:02, Geoff Canyon via use-livecode wrote: >> I tested three use cases, with variations, using ChatGPT for (live)code >> generation. There was a lot of back and forth. In the end, I solved all the >> problems I set, but in some cases I had to hold ChatGPT's hand pretty >> tightly. >> >> That said, I learned some things as well -- about LiveCode. ChatGPT's code >> for Fizz Buzz was faster than mine. >> >> My code was faster for reversing lines. But ChatGPT, when asked to "make >> the code faster" gave several suggestions, some of which were wrong or >> impossible, but one of them was my method, and when I said "write that >> option" it did, with only a few corrections needed. >> >> And one of the ideas, while wrong, caused me to think of a different way to >> solve the problem, and that way ended up being faster than my original >> solution by over 3x on reversing 10k lines. Getting ChatGPT to write this >> new method was *hard*. >> >> In any case, I wrote it all down in a google doc >> <https://docs.google.com/document/d/1W3j5WaFhYZaqSt0ceRQj8j160945gSwG_nyZsCBP6v4/edit?usp=sharing>. >> If you're curious, have a read. That URL is open for comments/edit >> suggestions. If you have any I'd love to hear them. >> >> Thanks! >> >> Geoff >> _______________________________________________ >> use-livecode mailing list >> use-livecode@lists.runrev.com >> Please visit this url to subscribe, unsubscribe and manage your subscription >> preferences: >> http://lists.runrev.com/mailman/listinfo/use-livecode > > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your subscription > preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
