graycat

49 ms·

391.
by graycat 3y ago
Of course, Galois and his fatal pistol duel were a long time ago, soooo, there are many polished presentations of Galois theory . E.g., in the abstract algebra text by I. N. Herstein can learn the basics of Galois theory in a few hours of
392.
by graycat 3y ago
Ah, good to hear that the IBM mainframes are still around, are more powerful , and that the software for the old IBM mainframes will still run on the new mainframes. So, yup, JCL still works! An 3270 series video terminals with 24 lines o
393.
by graycat 3y ago
The change that would make finding the next solution maybe not quickly would be to the basis matrix and its inverse from the last solution. Still, finding a new basis inverse would be much faster than starting from just the whole problem
394.
by graycat 3y ago
> common in LP formulations? If you want to consider the effects of war, inflation, something like the 2008 housing crash, economic depression, COVID, hurricanes, train derailments, etc., sure, if those hypothetical changes still yield
395.
by graycat 3y ago
Small point: If you want to do Monte Carlo on an LP (linear program), then using the simplex algorithm, for the first Monte Carlo trial , go ahead and find the optimal solution. Then for the rest of the trials, start with the optimal sol
396.
by graycat 3y ago
> Your response makes me wonder if the idea is not that RL can give more optimal solutions, but perhaps more robust ones? LP (linear programming), given an optimal solution, has some sensitivity analysis that nicely addresses robustne
397.
by graycat 3y ago
A linear programming (LP) problem is essentially just, for positive integers m and n and real or rational matrices 1 by n c n by 1 x m by n A m by 1 b 1 by 1 z, maximize z = cx subject to Ax = b, x >= 0 That is, an LP is a fully precis
398.
by graycat 3y ago
I studied LP (linear programming) from some of the most advanced researchers in optimization, including LP, in the world, led the class in a Ph.D. qualifying exam mostly on LP, wrote a Ph.D. dissertation in optimization, taught linear progr
399.
by graycat 3y ago
Start with an analogy: We've never seen a car before but find one, learn how to drive it, and are amazed, and ask "How does this amazing thing work?". We study the rubber in the tires, the disk brakes, the air conditioning,
400.
by graycat 3y ago
For statistical learning , the book I mentioned Nonparametric Statistics for the Behavioral Sciences , should make a good contribution to statistical learning . Some of the techniques are so robust , i.e., need such meager assumptions,
401.
by graycat 3y ago
Might consider, say, Sidney Siegel, N. John Castellan, Jr. 'Nonparametric Statistics for the Behavioral Sciences, Second Edition', ISBN 0-07-057357-3, McGraw-Hill, New York, 1988. So, "nonparametric" means make no assump
402.
by graycat 3y ago
> It feels like there is a certain amount of worthwhile stuff, despite vast numbers of people seeking ways to create it. You'd think with billions of people trying we'd get more things worth actually looking at. Have thought th
403.
by graycat 3y ago
Thanks! Actually I'm shopping for a smartphone! So, it turns out, actually, I AM in the "targeted market"!
404.
by graycat 3y ago
They assume that their readers know what WOA abbreviates and what Lumia is and apparently at their Web site won't say. Hmm.
405.
by graycat 3y ago
> What are your favorite methodologies for organizing digital life My guess is that my answer will not be common or popular with the Hacker News audience! (1) Emphasize simple text. For handling the text, use my favorite text editor KEd
406.
by graycat 3y ago
It took me a LONG time to accept what journalism actually is. For "The danger of delegating education to journalists", NAW. It's okay. Not entirely joking, we already do that! It's a standard part of nearly all col
407.
by graycat 3y ago
Several billion people understand and make good use of the standard HTML scroll bars. For any change, on the first day, only the programmer understands the new scroll bars. For an Internet user who each month or so goes to dozens, maybe hun
408.
by graycat 3y ago
All your issues have been responded to thoroughly. Here you are embarrassing yourself.
409.
by graycat 3y ago
> 1/10th the time is much faster. No, absolutely no, it's not in any meaningful or useful sense "faster" as in which algorithm is "faster". You utterly fail to get this point.
410.
by graycat 3y ago
> You are trying to argue something that isn't real to make a point that no one cares about and has nothing to do with this thread. In a word, you are wrong. I've been very, very, very clear again, over again, once again, yet a
411.
by graycat 3y ago
> I'm not completely sure what you are saying, but do you actually think a heap sort is in general faster than a quicksort or merge sort "in general" is not very specific. The main issue is the big-O expression. Again, if
412.
by graycat 3y ago
> First, I don't know where you got "gleason bound" from, For the answer and posted in this thread, I wrote: The Gleason bound? That's in one of the D. Knuth volumes The Art of Computer Programming. > Second, yo
413.
by graycat 3y ago
Versions of quick sort differ in how the partitions are determined. A guess is that some of the versions are not worst case O(n log n) for sorting n keys. In that case, for sufficiently large n, on a normal computer, any version of heap s
414.
by graycat 3y ago
Come on, guys: Early in my career, I had a really good career going. I paid a lot of attention to writing fast code. Some of that career was in a Navy lab, and some of the people there wrote fast code by going down to the assembly language
415.
by graycat 3y ago
The Gleason bound is n log(n) and says that no sorting algorithm based on comparing pairs of keys can be faster. Heap sort meets the Gleason bound so is the fastest possible in this context. Actually the usual versions of quick sort are sl
416.
by graycat 3y ago
"Faster sorting"? Heap sort achieves the Gleason bound and, thus, is the fastest possible sort by comparing pairs of keys. For keys not too long, radix sort can be faster. These facts have been very well known for decades. There m
417.
by graycat 3y ago
WOW! They are using BFGS! Haven't heard of that in decades! Had to think a little: Yup, the full name is Broyden–Fletcher–Goldfarb–Shanno for iterative unconstrained non-linear optimization! Some of the earlier descriptions of the
418.
by graycat 3y ago
Humans also use sound as in tires squealing, something going "thump, thump, thump", someone screaming, horns, sirens, "crash, tinkle, tinkle, tinkle", etc. Humans also use their sense of motion from the car sliding, rock
419.
by graycat 3y ago
> Now I drive a 27 year old car that has none of these 'features'. It does what I tell it to and when I tell it to, it doesn't phone home, and has no touch screen, but old fashioned buttons. I second your motion!!!! I was
420.
by graycat 3y ago
Some big companies, university computer science departments, etc. pursuing AI!!! Fine with me!!!! The crucial core technology , secret sauce , some math I derived, in my startup is NOT "AI" and, for the problem my startup is in

More ›