@Szabolcs if you go to the main page as opposed to the newest questions page, there is a box for emailing invitations, but it requires an email address.
I don't know who she is, but she followed the proposal since its launch and had a working blog link in her profile. Given the post she wrote, I expect some interesting non-standard questions from her. She is active on the Writers.SE.
I am just being self-appointed Chief Membership Officer again :)
@David I have no idea how they weight it, but it must be some combination of activity on the site and new followers. We have had several people start following it, waiting for the public beta.
@rcollyer not exactly, but I can imagine people tagging system when they should tag configuration - so imposing it as a tag synonym might confuse people. it is one we will have to watch
@rcollyer I forgot to mention, if you look at the Area 51 main page in newest order, the contrast between us and almost everything else proposed in the last nine months is amazing. The other three betas that started recently were all proposed over a year ago.
@rcollyer can we enforce that people never use a tag?
then it can be recreated only by someone with enough rep to do it. Now everyone can, since we're in private beta. In public beta it requires somehting like 150 rep and 300 in a graduated site
So even in cases where there are about 20-30 questions with that tag, they'll only recommend that you remove it manually (perhaps not all at once to avoid flooding the home page with edits) and let the background process do it
@rcollyer yeah, it's 300 on all SE sites, but 1500 on SO
SO, because of its volume and age, it's highly unlikely that you're going to think of a new, useful tag now
if you thought kittens had it bad for burnination, blacklisting would require kittens, ponies, unicorns and baby dolphins to be slaughtered before they do anything
moderators on Super User, which is the second biggest site in the network have to plead and pester for days on to get a tag blacklisted – and that after a lot of abuse. For new sites like ours, they ain't gonna bat an eyelid before refusing
@JM As per the comments, I restricted the list to only things that were specifically related to function/variable definition. The rest are much more mathematical in nature.
@yoda I figured that. I was just curious what it took. Which I got about 5 posts ago ... :P
let's make every function its own tag! that'll teach those folks who come up with crazy new tags... if it's blue in the front-end, then it's a crappy tag
btw, why OwnValues (plural) and not OwnValue? I'm leaning towards pluralization for the sake of consistency, but just in case I'm missing something, is there a case where a symbol can have two OwnValues?
So, does anyone else feel weird looking at the top users lists? I'm used to SO where we finally have a couple of gold users, and now, it's like, "where did all the upvotes go?"
would be nice to think about something not related to work for a while though, so I'm hoping for some new questions soon
I'm reduced to writing referee reports and replies to referee reports for the last few (and also the next few) days, in addition to being greatly confused over some calculation I am doing, so any distraction is welcome
I understand. I'm still working on my dft chapter in my thesis. But, my time has been rather curtailed this past week. Hopefully, tomorrow, I can get a good six hours straight to work on it.
@acl you just need a single stock template: "You suck, but I'll kinda sorta do a bit of what you suggested so that the editor doesn't think I'm a total jackass"
@yoda well, this guy has answer templates. 3 or 4, depending on the ref report. he showed them to me and he seems to be serious about it. crazy
of course he publishes at roughly twice the rate I do
@rcollyer it's worse, I applied the trick in my notes to noninteracting fermions to see what it does; it gives the correct answer, but I still don't see why it works (and it's an order of magnitude faster than doing it by brute force). guess I'm doing too many things at the same time and so forget everything immediately.
@rcollyer this is our normal lull - afternoon in Australia, too early for the Europeans, sleeptime for the Americans. I'm noticing a cycle in the visits/day stats on the Area 51 page. Today's is a higher trough than yesterdays, which is a good sign.
aha! I am now actively trying not to ask to see it (it's 5 in the morning here and I have been staring at such integrals from 9 yesterday morning until an hour ago)
It's straightforward to show that density, $\rho$, for uncorrelated one particle states, $\psi = \phi_1(\vec{r}_1) \dots \phi_N(\vec{r}_N)$, is simply $\rho(\vec{r}) = \sum^N_i |\phi_i(\vec{r})|^2$.
so can't you do it by parts after inserting resolutions of the identity? it works for a single particle (I can't do direct products in my head and can't see my notebook anywhere to write it down)
for the single particle state case, yes that's exactly what you do. But, for the many-particle state case, it isn't apparent if that can be done at all.
Anyway, the paper I'm working with makes that simplification as a way of being able to solve the problem and sweeps the correlated part into an unknown functional that has to be approximated.
And, I'm just trying to understand if it can or cannot be done at all for the correlated case.
nah it probably is something like that. i just apparently did something clever last time and can't work it out now. should be fine if I look at it fresh
if not, well, I trust myself :)
(apart from deciding to become a physicist, that may not have been so clever)
I've got a little troubleshooting puzzle that I don't think is worth posting on the site: the graph created by LogLogPlot[Exp[-x],{x,10^-8,10^8}] is different from the one posted by LogLogPlot[Exp[-x]/.Y->1,{x,10^-8,10^8}]. Anyone know if this is a bug in Mathematica? (version 8.0.1.0)
Exp[-x]: blue part only; Exp[-x]/.Y->1: blue and red parts
No, it's not there; he seems to be describing a hypothetical use. But Mike's answer to another question linked to in the OP would benefit from the use of Unique[].
On the surface that question seems like a low hanging fruit that I'd love to pounce... but I guess you probably know what the doc says and its basic usage... it probably needs a Leonid style long answer to put that puppy to sleep
This question started me thinking about how Mathematica detects multiple functions being plotted. I find that I really do not understand the process.
Consider:
Plot[{1, Sequence[2, 3], 4}, {x, 0, 1}, PlotRange -> {0, 5}]
I can understand that Plot finds three elements in the list initia...
On that note, that's part of what made it a bit tough for me to switch from version five. Stuff that I was used to doing didn't work, and stuff I knew wasn't supposed to work suddenly did.
@David I haven't done tests with the current version, but back in the day, MATLAB outdid Mathematica, even when the latter had already started implementing SparseArray[].
I tend to like Mathematica for prototyping. I want to do something, I write a Mathematica mockup. If it works nicely, then I figure out how to redo everything in language X.
I would tend to agree with MATLAB being better with matrices. Sure, list handling in mma is pretty good, but there are several convenient features in matlab that are missing in mma. Also, when working with matrices all the time, I'm more comfortable thinking of rows and columns than levels of lists
I always find it hard to think in basic programming languages again when you've got functions like NIntegrate at your hand in Mathematica that integrates arbitrarily messed up functions.
On that note: one sees that in linear algebra, it's more natural to treat matrices by columns. Mathematica flips that convention. Makes for trouble when using functions like Eigensystem[]...
On a side note, it's quite surprising that everything keeps working despite me constantly forgetting whether the first or the second index is row/column of a matrix
The traditional storage format stores the two triangular factors in one array for economy reasons. But sometimes, you need the triangles themselves for further manipulations.
Also, a lot of operations on multi dimensional matrices (3D/4D) can be sped up by "vectorization" instead of needing to loop over dimensions... in other words, you flatten it out to a column vector and work on that and reshape it back the way it was/should be. ind2sub and sub2ind are very handy in that regard in converting from the vector's index to the corresponding index in the matrix
The no overhang default is useful in imageprocessing, where you actually have to account for the overhang and ignore it to properly localize a template in an image
This question started me thinking about how Mathematica detects multiple functions being plotted. I find that I really do not understand the process.
Consider:
Plot[{1, Sequence[2, 3], 4}, {x, 0, 1}, PlotRange -> {0, 5}]
I can understand that Plot finds three elements in the list initia...
