Posted by chemist on May 7, 2004, at 4:00:38
In reply to Re: LET'S DUMP THIS CRAP, DR. BOB!!, posted by cubbybear on May 7, 2004, at 2:54:35
> > > Sorry Chemist, I adjusted the spelling a bit. Curious bout the monte carlo applied to business solutions. Even with the spelling changed i'm still asea. Give me a hint.
> >
> > start with metropolis' article in j. chem. phys., circa 1957 or 1958 (metroplolis bias-sampling ring a bell?)...start an ensemble of random ``walkers'' with a potential function that need not be - and is not - differentiated. you randomly move each walker - here, let's assume a Cartesian space, not Minkowski 4-space, i.e,, time-independent - and you have previously computed the kinetic and potential energies for you ensemble of walkers. after the move, you evaluate the ``energy'' of each walker: if it hgher than the (new) ensemble average, discard the walker. if E_{walker} <= E_{ensemble}, keep walker but weight the contribution with a boltzmann factor, i.e., exp(-beta*E), where beta == (1/(k_b}T) (yes, i write everything in plain TeX, not LaTeX), and note that temperature here does not necessarily jibe with the traditional temperature definition (instead, market cap, P:E, trading volume, etc.). then branch for generation of new walkers to keep your ensemble constant in N, which entails weighting the already weighted walkers that survived. very quick, very precise, very easy to code, and you can actually get the *global* minimum on the PES. i use a variant - quantum diffusion monte carlo - where a change of variables from t to i(tau) (i == sqrt(-1)) in the time-dependent schrodinger equation leads to fick's second law of diffusion. problems: expectation values are very, very hard to extract (see work by ann mccoy at ohio) but you can get the quantities you need - in many cases - by following this recipe (QDMC). also, you can do quantum simmulated annealing - vary hbar from 1 to 6, usually - and for lennard-jones clusters, global minima are reached in many cases. if you define your kinetic and potential terms as functions of business solutions, the results are quite attractive....all the best, chemist
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> I didn't have time to really peruse Psychobabble for a couple of days but started getting suspicious--from intuition only--about this person named chemist. Then when I returned and spotted the mini-controversy surrounding his/her qualifications, I realized that I wasn't alone.
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> Then, as I delved deeper into the threads, I started seeing all sorts of slang, American regional gibberish, and all manner of irrelevant and inappropriate postings--inappropriate to the essence of what this board should be all about. In the two years I've scanned this board, I've never such garbage--enough to fully turn me off.
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> Perhaps this should be directed to Psychobabble Administration, but before I resort to that, I'd like to see a consensus as to whether regular Psychobabble users are on my wavelength. Maybe I'm in the minority, maybe not. But all, I'm saying is, *Let's get rid of all this junk, and stop discussions, like the above, NOW!!*
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hey champ, does my ``garbage'' compare to posters who want information on how to get on-line meds without a prescription, users of ecstacy who want to keep partying, or myriad posters who are being misdiagnosed and/or mistreated by their doctors? tell you what: the ``American regional gibberish'' comment is more than inappropriate, and the ``irrelavant and inappropriate'' postings are what, exactly? my subtle tries to inject a bit of humor into a post (e.g., considering myself an honarary Aussie because i listen to AC/DC?) are the best that i can do given the severity of problems presented here, and a bit of levity (you might need to look that one up in the OED) is what is called for in a population of individuals who need information, solace, and hope. as you have been posting here for 2 years, i am sure you have read with great pleasure - and can identify with - the ravers who steadfastly deemed ecstacy use as perfectly reasonable (again, consult the OED if you are at a loss) drug. keep 'em coming, and again, thanks for all your contributions. and i am interested in your qualifications, so let's play ball: i'll send to you my CV, and you can send me yours. but in the meantime, by all means, call for a vote to ban me from this site. i will abide. looking forward to hearing about your qualifications, chemist
poster:chemist
thread:344054
URL: http://www.dr-bob.org/babble/20040505/msgs/344282.html