You can choose a dropdown cell option in the private stylesheet for that notebook (which you can eventually save as a standalone one). You'll find this in the top left.
My preferred way of doing it is to start writing something, which creates a cell, and then Cmd-Shift-E to show the expressions. Then I replace whatever is in there with what I want to enter
Oh, and to get to the private stylesheet, Format > Edit stylesheet
Yeah, you can also enter it in the box next to it (I'll admit, I didn't realize StdForm was not there... I use the alternate approach I mentioned above)
With Format -> Edit Stylesheet... it is possible to adjust text-properties, text-colors, formatting of equations, etc of a notebook and to use this style-definitions again by installing it as Stylesheet.
Lately, I saw a very nice screen-shot of a notebook and I noticed, that not only the text-pr...
@halirutan now I get to play with the syntax colors to my heart's content! I can't stand the defaults, and the ones I came up with after nuking my front-end's init.m file, I can't seem to reproduce the ones I had. This will make it easier. :)
@rcollyer I saw. Answered a question on meta. I'd really only participate in certain information management type questions rather than library questions. Ironically, it might be of interest to my ex (InfoScience professor).
Hi @BrettChampion - do you know if the video from yesterday's presentation will be available for later viewing? How did it go?
Time zones are a pain. I remember for the Virtual Conference last year the support staff had to roll into the office around 3am or something for the version that was aimed at Europe.
Ah, I'd seen Yu-Sung had stopped by, by not Vitaliy. I originally popped in to see if Yu-Sung was still here. (And hit the 'Join' button from the transcript instead of the 'Info' button by accident.)
Seems like it is a general ramp-up of promotional events - I notice that the special events has a "System Modeller" virtual conference scheduled for mid June.
Today's event was during business hours, so it just means I spent a bit less time working on Kernel development. All told I think it took up ~8 hours this month, which isn't too bad.
And in any case, it's fun to do something different for a bit.
@BrettChampion considering how many people were posting in the chat room afterwords, I would say so. And, my questions were fairly advanced, so I did not expect them to be answered in that forum, anyway.
@Verbeia You can use Labeled[<DateListPlot>, label]. DateListPlot doesn't currently support Labeled as a wrapper for the data (which does work for the XXXXChart functions.)
I want to make a 2D plot where the x-axis is flipped so the higher numbers are on the right and lower numbers are on the left.
I've managed to do it by flipping the data and making new Ticks but this solution is manually and requires manipulating the data. I was hoping there was a better way.
F...
@BrettChampion thanks. I don't remember reading that answer. Useful. I wonder why it works though, as it is not listed as an option of either ListPlot or Graphics.
I think it'll be a while before Graphics supports ScalingFunctions. As for ListPlot, there are may be gaps in how some of the options are handled when ScalingFunctions is used. Something I need to look into.
I have a (list of words)[alcor.concordia.ca/~vjorge/Palavras-Cruzadas/…, without mathematica formatation, it's not {a,b,c,d}, it's just one word per line, how can i transform it in a formated list?
I have a (list of words) [alcor.concordia.ca/~vjorge/…, without mathematica formatation, it's not {a,b,c,d}, it's just one word per line, how can i transform it in a formated list?
@BrettChampion right. a lot of preprocessing going on. But, as ListPlot did not have the option ScalingFunctions listed, I thought maybe it was in the parent object Graphics. In this case, neither => undocumented. :P
Anyone knows how MemberQ works in Compile? It's in the compilable functions list and it doesn't call back to the main evaluator, but it works weird. Try Compile[{{x, _Real, 1}}, MemberQ[x, 2]][{2}]
@Rojo Weird ... it does work if you set the type to _Integer.
@Rojo I think the reason is that the 2 in MemberQ[x,2] is an integer, and since the type of x is real (whatever you pass to the function either gets converted to real or throws an error if it can't), 2 can never be part of x.
@Guillochon And of course it's built into Plot, so I suppose you can't use Plot for your application, right? (I couldn't because I needed more control.)
@Guillochon Mine didn't have a sharp asymptote (it was bounded), so I did this:
compute the function on an equally spaced coarse grid, then refine like this:
if we have three successive points on the curve, A, B and C, and the angle between AB and BC is greater than a threshold, then insert two new sampling points at the midpoints of AB and BC
This is exactly what Plot does, BTW
(sorry, my code is on an external drive, would have to dig it up ...)
@Guillochon My function was very expensive to calculate, a whole run (to sample a domain) could take hours, so it was important to be able to stop midway, and then refine the sampling mesh without throwing away previous results. This is not (easily & reliably) possible using Plot
Pieced together from existing bits, here's one possibility. This is a start.
Please upvote if you think it's ready to be posted, comment if you think something needs to be changed, or even better: post another one.
Full code follows. I chose to make it fully in Mathematica so everyone on thi...
@RM I agree, and it's also very badly stated (he just dumped his code, as do more and more people recently)
@rcollyer I posted also a speedup in the other question, but in the end I got annoyed because it took me far longer to locate the relevant parts of the code than to modify them. the first half of the code he posts is irrelevant (literally, you don't even need to look at it), as is the last 1/3; his real question is`PD1` is slow, how do I speed it up
wasted 30 min to work that out (admittedly I had time to waste, so...)
When I tried to present some pre-calculated density histograms inside Manipulate I noticed that the display of DensityHistogram is extremely slow. Here is a simple benchmark:
Second[x_] := x[[2]];
data = RandomVariate[BinormalDistribution[Abs@Random[]], {5, 10^4}];
histograms =
DensityHistogr...
maybe I should also just dump my pages of code here and ask "why does this take 3 weeks?". at least I've tried answering some questions once in a while!
@acl apparently, about 5-10 years ago, the guys at NOAA were able to exactly predict the state of the weather ... 10 hours after it had occurred. So, 3 wks for a 10ms process is not as bad as it sounds.
@acl I'll mail it to you later (to your gmail). It has awful performance, I only needed it a few times to reduce the number of points in some figures (and reduce figure size)
One way we can promote this site is to create a community promotion ad to be shown on other SE sites. Each graduated SE site has a meta question where people can submit these ads (math, physics, stats), and if they receive enough upvotes they will be automatically shown by the system.
If we are ...
@Szabolcs Yes, I did recognize the nautilus shape; I more or less know how to manipulate the logarithmic spiral, which is why I said I could fake the general shape of the surface...
...but the methods I know for modifying surface parametric equations to have ridges tend to be unreliable for things with non-circular cross sections.
@RM I'm a perfectionist. ;P (But seriously, I've managed to give a torus some ridges by tweaking its parametric equations; there should be something that will work for that.)
ParametricPlot3D[ With[{r = (v Exp[s u] + Exp[s (u + 2 Pi)] (1 - v))}, {r Cos[u], r Sin[u], r ((v - m)^2 + z/(2 Pi) u + 0.2 v (1 - v) Sin[10 u])}], {u, -2 Pi, 6 Pi}, {v, 0, 1}, PlotPoints -> {100, 6}, PlotRange -> All]
m = 0.53 z = m^2 - (1 - m)^2 s = 0.1
@JM Sorry, no time to fix some misunderstanding about how I used the radius and no time for a better ripple function than Sin ... got to do the dishes and make dinner
Today I’m excited to be able to announce that our company is moving into yet another new area: large-scale system modeling. Last year, I wrote about our plans to initiate a new generation of large-scale system modeling. Now we are taking a major step in that direction with the release of Wolfram SystemModeler. SystemModeler is a [...]
Piggybacking on this, I am somehow not fully convinced that I can't save data generated by a calculation in a mathematica file so that when I re-launch said file, I wouldn't have to run my calculations again.
I ask because I use NDSolve for 4th order non linear PDEs and sometimes I need to run i...
@MrWizard I never noticed that ... I almost lambasted a person for re-posting a question that had been closed as being off-topic here. Note: I was on sci-comp at the time.
@Szabolcs I'd say no, unless it was built on top of mma and mma is accessible.
It appears that they're separate but compatible systems. So, I'd say that interfacing the two is on topic, but questions only on SystemModeler are off-topic.
@Szabolcs: did you derive the equations for the nautilus surface yourself? It's quite nice! Coloring it was slightly difficult, but I managed to do so...
(...though I could probably have spaced the ribs logarithmically so that it looks better.)
@JM Yes, I did, step by step. I used to love to do parametric surfaces when I was in high school (it was a good exercise too, just to figure out how to get e.g. a sphere, and getting all kinds of shapes---mostly tori---while trying)
@belisarius Yes, that's why I said it would have looked more realistic if the stripes were log-spaced, but I will have to figure the proper color function later...
@RolfMertig Maybe so we can do a := Sequence[1,2,3] then re-use it? On yesterdays visualization seminar they did something like options = {PlotRange -> ..., Frame -> True, ... etc.}, then used it as Plot[..., options]. I did not know that the options could be in a list, and I would have used optiosn = Sequence[ ... ] myself instead. That could be one application (but it turned out it's unnecessary ...)
@Szabolcs But suppose := would not be SequenceHold I could just do a:=Apply[Sequence, {1,2,3}] . I also always wondered why If is SequenceHold. I think it should not be (so I could do If[x>1, {3,4},Sequence[] ]; Now I have to do something like ReleaseHold[If[x>1,{3,4},Hold[Sequence[]]]]
@Verbeia Your modification to the ad seems to be very popular :-) I think after a full 24-hour wait we can go ahead and post them (just to make sure all time zones got a chance to wait). @whuber has the idea that instead of just choosing one ad, we can cycle through them periodically.
@acl That above is a very quick and very dirty Ramer-Douglas-Peucker which I used to downsample some simulation output before creating figures. It's quite slow and I only used it on curves that had a monotonically increasing x-coordinate (something like a function that you can show with ListPlot). If you improve it, let me know!
@acl SetSystemOptions["ParallelOptions" -> "ParallelThreadNumber" -> 1] should affect the MKL (e.g. LinearSolve which is multithreaded), and under Edit -> Preferences -> Parallel there's a setting for the parallel computing tools (how may kernels to launch)
@Szabolcs no, it doesnt affect linear algebra computations
thanks though
in case anybody knows something useful:
my problem is not to avoid launching kernels, it is that my program involves a number of matrix multiplications inside an NDSolve, and this seems to grab as many processors as it can within a single kernel.
this means that when I run it on some machines at work, it goes and grabs 10 cores.
it is not faster, though. and the actual problem is that it counts as processor time, so I end up having to request the queing system for days of computing time; this means I end up waiting for 10-20min for my jobs to run
so if anybody knows of any other ways to control this kind of thing, I'd appreciate being told.
our logo is a flower-like object with the world "funnest" in the title. amazing
@Guillochon Let me se if I understand. Are you trying to integrate lef[n] over Xi where lef is of the form lef[n_] := Theta[Xi] /. NDSolve[eqns, Theta[Xi], {Xi, ...}]
I think the problem could be that in NDSolve you're solving for Theta[Xi], so the solution is of the form Theta[Xi] -> ..... This means that Theta[Xi] /. NDSolve[..., Theta[Xi],...] will work but Theta[2.] /. NDSolve[...], say, will just return Theta[2.]. Instead you could try lef[n_] := Theta[Xi] /. NDSolve[..., Theta,...]
@Szabolcs Glad everyone liked it. But really, credit to @@wxffles for coming up with the design and @Szabolcs for the ad design. I just wrote a different slogan and played with colors.
@acl I first heard "funnest" in a keynote by Steve Jobs. I think it was about Photo Booth. It's not really a word, but that will get attention.
Pieced together from existing bits, here's one possibility. This is a start.
Please upvote if you think it's ready to be posted, comment if you think something needs to be changed, or even better: post another one.
Full code follows. I chose to make it fully in Mathematica so everyone on thi...
When I tried to present some pre-calculated density histograms inside Manipulate I noticed that the display of DensityHistogram is extremely slow. Here is a simple benchmark:
Second[x_] := x[[2]];
data = RandomVariate[BinormalDistribution[Abs@Random[]], {5, 10^4}];
histograms =
DensityHistogr...
