Wolfram Mathematica

Mr.Wizard

2:23 AM

@R.M I've got just a minute.

R.M

Well, just alerting you to the chap whose post you edited... not his first time.

Mr.Wizard

@R.M hardly the first time...

I'm still trying to teach, but losing hope.

R.M

Annoyed several of us before and his arbitrary capitalizations and lowercasing + backticks everywhere have the pattern of a deliberate troll

Mr.Wizard

I'm not sure about deliberate -- I suppose we could have attracted an actual troll, but I am more inclined to think simply weird and lazy. :^)

R.M

Ok, just letting you know, since I don't recall you being around the last time

Jul 16 at 13:22, by R.M

The reason I think he's doing it deliberately, is because he used correct capitalization (for the most part) in this question, which was his first. Note that it has not been edited, so all of it is his. No ellipsis, no arbitrary caps

Go a few more comments up from there (Szabolcs' and then down from there)

Mr.Wizard

2:27 AM

Okay, I missed that. And I also just saw your comment below mine on his recent question. I guess this will have to be dealt with. :-/

R.M

Also, Sjoerd said he warned him... not sure if via mod message or otherwise:

Jul 16 at 15:15, by Sjoerd C. de Vries

@RM I warned him one last time. If he's going to repeat this again this will be the first time I'll suspend a user. He's indeed Indian, how did you know?

Anyway, thanks for popping in. I won't keep you around longer :)

Mr.Wizard

Okay, I've got to go now but I'll address this with the other mods when I can.

Bye, my little green friend. ;^)

R.M

Hocus pocus poof! :)

I guess that's more magicianese than Wizardese :P

R.M

2:51 AM

Hello @SjoerdC.deVries

Still in Cape Cod?

Sjoerd C. de Vries

@R.M Hi! Yes, two days before I leave.

As to your quote above, I believe I did that in a comment

R.M

Oh, ok. Comments have generally fallen on deaf ears :)

Did you visit Martha's Vineyard (or are you staying there)?

Sjoerd C. de Vries

No, we are staying in Hyannis.

Walking distance from the Kennedy compound

R.M

nice. I spent about 3 months a few years ago in cape cod during the summer. Easily one of the best times I've had. Although, it sucks to be there in winter

Sjoerd C. de Vries

I can imagine that. Hyannis is pretty small and there's not much to do except for swimming and related things.

But that's perfect for now. The rest of the vacation has seen more than sufficient activity.

R.M

3:01 AM

Heh, most of the cape is like that. Good place to relax, but not for the party type

Sjoerd C. de Vries

I guess, I'm beyond the party age.

R.M

:)

Sjoerd C. de Vries

@R.M will you be on vacation any time soon?

R.M

For a little bit in a couple of weeks... I have a short workshop that I'm attending in the first week of August and will spend the rest of the week + weekend in New York City

I might head out to DC too for a day, but that's not fully decided though

Sjoerd C. de Vries

Thats what you would call an American vacation. Short.

R.M

3:07 AM

:)

Sjoerd C. de Vries

Did I ask you whether you intend to go to the WRI tech conference?

R.M

I'd like to, but I won't be financing myself — can't afford it.

Sjoerd C. de Vries

SE is likely to subsidize this.

R.M

I'm considering whether I should skip it this year and perhaps attend the next one instead. I also have another conference starting the monday right after, so 10 days of conference might be overloading (although mma will be the fun one)

Sjoerd C. de Vries

17

Q: How can I get Stack Exchange to send me to a conference?

I read Supporting Community Conferences, which states, Depending on the circumstances and location, we can also sponsor community leaders to attend an event on behalf of their site. We will subsidize your costs to attend, within reason, and provide you with a bunch of swag to use as an ice-br...

R.M

3:13 AM

Yeah, I've seen that one

Sjoerd C. de Vries

We got a message from Aarthi about this, so it seems that it's very likely we could send one or more of our most active community members.

R.M

Are they going to take the initiative and post the meta question for all or is it up to each one to contact them if they're interested?

Well meta post is the first step anyway... regardless of who it comes from

Hmm. I don't get this — a one day registration is $50, and for the whole 3 days is ~$500... something doesn't compute

They do say one per person, but c'mon, how hard can it be to register 3 for yourself (as long as you have 3 credit cards)?

Sjoerd C. de Vries

I think we are supposed to do the Meta posting, but I thought it good to check plans informally here before posting.

R.M

Do you plan on attending this year too?

belisarius

@R.M perhaps the $500 includes a Mma 5.2 license

Sjoerd C. de Vries

3:23 AM

Last time Daniel L took care that I could register for a low fare, instead of the commercial one.

belisarius

@SjoerdC.deVries Did you pay with your own wallet?

Sjoerd C. de Vries

@R.M I would love to, but my problem would be vacation days.

@belisarius Yes, I did. I guess I must be rich.

belisarius

@SjoerdC.deVries So, that was nice from DL

My plane fare would be more much than $500 :(

Sjoerd C. de Vries

Same here

But if you follow the above link it looks like SE would be willing to subsidize all costs

R.M

They'll go the extra mile to fund you if you're a speaker (you'll have to spend 2 minutes of your talk plugging in SE)

Sjoerd C. de Vries

3:28 AM

Fair enough, I'd say

R.M

I agree

They flew out one of the TeX mods from Germany to India for a conference because he was giving a talk, so there is precedent

belisarius

@R.M Now we only have to prepare a presentation about the "long integrand" question, and we are done

Sjoerd C. de Vries

Last time I thought we were on the verge of v9, which happened to be not the case alas. This time however....

;)

R.M

@belisarius hehe

belisarius

@R.M I have a plan.

I prepare the talk. Sjoerd presents himself as the "long integrand" guy. And you do speak out the integrand by heart. Three grants needed.

R.M

3:33 AM

Ok, I have a question: what is the simplest way to check that the line Line[{{2,1}, {3,1}}] lies outside the polygon Polygon[{{0, 0}, {1, 0}, {1, 1}, {0, 1}}]?

belisarius

Draw it

R.M

programmatically

without long integrands

belisarius

damn

I knew you had a restriction

R.M

It's for this answer of mine:

10

A: Build a refined grid based on intersecting line

Here is my implementation using Graphics primitives and rules. First, we start with a single square and build up a test grid: square = Polygon[{{0, 0}, {1, 0}, {1, 1}, {0, 1}}]; grid = Graphics[{EdgeForm[Black], FaceForm[None], Table[Transpose@First@square + {i, j} // Transpose // Polygon, {...

belisarius

@R.M I remember Yaroslav did that things by using SatisfiabilityInstances

let me check

R.M

3:37 AM

ruebenko pointed out an edge case when a line shares an edge with a polygon. He had a pretty simple fix to check, which is to form a triangle with the two points of the line and each point in the polygon. If the determinant is zero, then it is an edge

That's neat and I've implemented that (not yet edited into the answer), but the determinant is also zero if the line is parallel and collinear to an edge, but not actually on the edge

@belisarius This one, you mean?

belisarius

@R.M No, it was one about polygons or polyhedra

@R.M sorry, I can't find it. Perhaps I dreamed it

R.M

@belisarius Probably. The question I linked to is the only one on Stack Overflow that has SatisfiabilityInstances in it

Were you thinking of a MathGroup post then?

belisarius

sorry, I can't remember

R.M

Ok, I think I found what you were thinking of: mathematica-bits.blogspot.com/2010/12/…

@Mr.Wizard Continuing our earlier conversation, this is why I think he's either trolling or the account is being controlled by 2 (or more) users: Compare this question (and today's and all other negative posts) with this one. There's no way the same person asked both.

Sjoerd C. de Vries

4:13 AM

@R.M it's a strange guy. I wonder whether it's really trolling, as even these dumb questions take some effort. I tried examining the ip addresses, but the mod tools don't give consistent results.

Verbeia

@SjoerdC.deVries I think it's two people working on the same problem. One writes lazily, the other is more diligent. Compare versions here: mathematica.stackexchange.com/posts/8714/revisions and you will see what I mean.

R.M

@SjoerdC.deVries there's 2 clear patterns... one with reasonably written questions and the other with arbitrary spellings and backticks.

rcollyer

@Verbeia interesting theory. you may be right.

R.M

4:31 AM

Also, my impression is that the lazy writer doesn't know how to respond to comments or do what we ask of him... the other chap edited his post as MikeH asked him to and replied too.

The one who understands is probably not aware of these comments, because the other chap has already read them and dismissed from his inbox

Maybe a mod message so that a note is put in his email?

belisarius

wow Sherlock is working hard

Sjoerd C. de Vries

Sounds likely to me. I'll try to come up with a message.

R.M

Thanks! :)

Sjoerd C. de Vries

I see that I have to leave that for tomorrow. It's a bit late. See ya.

R.M

bye

Mr.Wizard

5:29 AM

@belisarius Indeed.

It would be great if we could get the more articulate personality in Chat.

belisarius

@Mr.Wizard They popped the poor guy's eyeballs out just to see their color :)

Mr.Wizard

@belisarius uh... Is that a figure of speech I'm not familiar with or are you in a particularly sadistic mood? :O

belisarius

@Mr.Wizard Not sure. Could be both

@Mr.Wizard I am looking "The Shining". That may explain a few things

Mr.Wizard

@belisarius hehe, yes.

Szabolcs

7:42 AM

is it not possible to post questions without registering?

Szabolcs

7:56 AM

I wonder if this will slow down new questions

Graduation might have the opposite effect than many thought: fewer questions, not more

Szabolcs

9:46 AM

Verbeia

12:15 PM

@Szabolcs Interestingly, though, traffic is coming back up.

Verbeia

12:32 PM

Anyone home? I'd like to get a second pair of eyes on this blog post before I hit "publish".

Mr.Wizard

@Verbeia I canot promiss quallity prooffreeding, but I'll take a look at it. :o)

Verbeia

@Mr.Wizard thanks - it's almost bedtime here and I'd like to post tonight here

Mr.Wizard

@Verbeia Link?

rcollyer

@Mr.Wizard It was in the other chat room.

in Mathematica.SE blog, 7 mins ago, by Verbeia

Can someone please offer a second pair of eyes? http://mathematica.blogoverflow.com/?p=255&shareadraft=baba255_501138aeab701

Verbeia

@Mr.Wizard over in the other chat room

Stack Exchange

1:34 PM

Mathematica - Stack Exchange Blog: Build Your Own Logo with Mathematica (and a Few Friends)

verbeia on July 26, 2012

Mathematica has powerful graphics capabilities that can be used to explore the space of graphical forms in a very flexible way. Wolfram Research itself has already published a blog post showing how to manipulate various corporate logos, so it should be no surprise that the Mathematica StackExchange community came up with its own logo – not once, but twice! – and that we did it using Mathematica.

This isn’t my story alone. wxffles had the original idea; J.M. came up with a variant that allowed the colouring to be defined in a very granular way. I took their code and started playing with it, and …

Jin

3:34 PM

@Verbeia thanks for the great blog post!

@Szabolcs the code block scrollbar has been fixed on the blog

Szabolcs

3:58 PM

Thanks Jin, that's really great!

Just in time

R.M

5:09 PM

@Jin Can we also have syntax highlighting used on the main site activated on the blog?

Jin

@R.M I can check with the devs. I'm not sure if we use syntax highlighter js on the blog

R.M

Ok, but if not, it would be nice to have it :)

Jin

agreed

Jin

5:57 PM

how does one go about creating something like that in M?

I think the shapes are easy to do, I'm more asking about the randomness of the color distribution

Szabolcs

6:09 PM

@Jin I would absolutely love to do that, but unfortunately I just do not have time tonight. What I would do: 1. Create a triangle with a random colour. 2. Subdivide it into smaller ones (each edge is divided in 5), and blend a random colour onto the base colour of the triangle. 3. Recursively repeat the subdivision.

I'm not sure it would make the same effect, but that's how I'd try. Of course with the limited blue-yellow-red-purple palette.

@R.M @Jin We already have syntax highlighting activated on the blog, but the syntax highlighter plugin doesn't support Mathematica by default. There were so many problems with formatting in WordPress that I just don't want to ask to have too many plugins installed right now.

I had to change some of the <pre> to MarkDown again because newlines were doubled ... but MarkDown code blocks have their own problems.

@R.M Did you disable the visual editor when I asked? It eats MarkDown for breakfast...

There are also alternating dark-light lines.

@Jin Do bring some more please later, I will enjoy trying to reproduce them. I like this kind of thing.

R.M

@Szabolcs Yes. Also I've only used the HTML editor before

Szabolcs

6:28 PM

@R.M the reason I was worried is that some said it sometimes loads the visual editor the first time you open the post, which destroys some markup right away.

R.M

I just tested that now on a test post... didn't seem to remove any markdown as far as I can tell

Jin

@Szabolcs bookmark this. crowquills.com i'm a HUGE fan of his work

3

belisarius

HI!

A question on etiquette

There is a question posted here which has been already answered in SO. How to proceed?

Close and comment?

Szabolcs

No, don't close.

belisarius

copy answer (crediting) and mark as CW?

Szabolcs

6:39 PM

you may want to flag the SO question for migration, if it's really good, then we close as duplicate when it arrives here

belisarius

@Szabolcs Yes, it is really good

Szabolcs

Then flag, and explain in the message that we want it here because it's good and we want to mark something as its duplicate

I did it before

belisarius

a way to circumvent a known bug

4

Q: Mathematica: Retrieving PlotRange from Histogram

I know that one can retrieve PlotRange of a plot by using AbsoluteOptions[plot,PlotRange] but that won't work on Histogram. Here an example: In[1099]:= data = {-1.2056, -1.46192, -1.30053, -2.52879, -0.99636, -1.73904, -1.164, -1.83398,-0.97505, -0.503256, -0.63802, -0.785963, -0.711821, -0....

mathematica plot range histogram retrieve

@Szabolcs ok. doing that

@Szabolcs flagged

Silvia

@Jin This is fantastic! I love them!

Jin

6:56 PM

@Silvia I tried to do something simliar to his style in Illstrator long ago, but the results weren't great.

Silvia

@Jin I would absolutely like to try it with Mathematica :) OK I'll do it maybe tomorrow, tonight I have a CellularAutomaton for snowflake to work on :D

Wolfram Blog Feed

Wolfram Blog: Tracking the World Records

posted on July 26, 2012 by Daniel Lichtblau

With the 2012 Olympics coming up, and records waiting to be broken, it might be a good time to consider some aspects of track and field. I need to write this now, because once the track part of the Games is underway, I fully intend to spend quality time with a television set. Why do [...]

Szabolcs

7:44 PM

@WolframBlogFeed Maybe we can make our blog posts longer too.

@Jin If I manage to create something nice, perhaps it'll make a good blog post

Jin

@Szabolcs that'd be awesome!

belisarius

@Szabolcs q was migrated from SO

Voted to close as dup

Szabolcs

@belisarius and all: I voted to close this one as a duplicate of this one before, but the votes expired.

All that ad needs now is a halftone effect.

But if I were a teacher, I wouldn't like it at all. Asking Mathematica to do one's homework is not a good way to learn. Maybe to verify ...

Hello @DavidZaslavsky, long time no see.

David Zaslavsky

@Szabolcs Hi :-) Yeah, I haven't been around that much lately

but I have been admiring the site design since you graduated

belisarius

@Szabolcs Although the answers converge, I think the first one is specific for NR

Szabolcs

7:58 PM

@belisarius wasn't the question: how to call NR functions from Mma? That's the same as asking, how to call C++ functions from Mma. Well, technically it's a special case, but that won't make the solution any different.

@DavidZaslavsky the blog has launched too

David Zaslavsky

@Szabolcs nice, that one's going in my RSS reader

belisarius

@Szabolcs Some could have developed a solution for NR. Or some could do it in the future

Szabolcs

@belisarius That solution would be exactly the same as a generic C++ solution. In practice, an answer would show how to call one particular NR function, with full code. The OP would still have to write his own code to call other NR functions. It's not different from showing how to call a non-NR function and starting from there. There's nothing special about NR that makes it easier to call than some other numerical function that's not in the book ...

I really don't see how an answer can be specific to this question unless it points to an existing NR integration package, which doesn't seem to exist

belisarius

@Szabolcs The same could be said about TetGen, however you already know that a specific implementation was done

Silvia

8:18 PM

@Szabolcs off topic, I always don't like that ad. Change it to a boy or cat would be nice :P

btw is it ok to answer an old and accepted question?

(when I thought I may have some interesting idea about it.)

David Zaslavsky

@Silvia yeah, absolutely

That's part of the whole idea behind Stack Exchange, that questions never "expire"

belisarius

@Silvia Also, the original poster could change his mind and accept yours, if it fits him better

Silvia

@DavidZaslavsky Great :) Although I have to spend more time to test it.

@belisarius Thanks, I see:)

acl

10:09 PM

@R.M OS X 10.8 works just fine with mma and everything else so far (you need to tell xcode to "install the command-line version" of gcc et al for compilation, but that's all)

so upgrade without fear :)

Sjoerd C. de Vries

@Szabolcs I feel the question is also about which parts of NR would be a good target for linking to Mathematica. it's a close call, but I chose to let the question stay. let is have the benefit of doubt. (though I'm a fan of the Mythbusters: "When in doubt, C4".)

@verbeia Great blog post! I noticed we have settled on UK/AU English, right?

@acl=jsb?

acl

@SjoerdC.deVries ListContourPlottted, no less

although that is a bit presumptuous of me I guess

acl

10:42 PM

I find it amazing that this can be done with so little code...

belisarius

@acl Also amazing is using Putin as a model

acl

@belisarius or amusing

belisarius

@acl This is not really a Mma question

I upvoted it, but it should migrate somewhere else

4

Q: Finding a Concave Hull

I have a 3d clustered data: data3D = Import["http://dl.dropbox.com/u/68983831/process.vtk", "VertexData"]; Graphics3D[Point[data3D]] Since process.vtk only consists of data points, no polygondata polysurface = Import["http://dl.dropbox.com/u/68983831/process.vtk", "PolygonData"] (* out ={...

graphics graphics3d computational-geometry mesh tetgenlink

math.se probably

acl

I was wondering about it. It looks like a math.se question but I thought I may be missing something.

belisarius

11:00 PM

@acl It is. At least until a good definition of Concave Hull is there.

I am pretty sure it is not trivial

Think of the concave hull of the number 5 in a dice

belisarius

11:51 PM

Please merge this with this

R.M

@belisarius I solved my line-poly problem from yesterday

belisarius

@R.M link?

R.M

The SatisfiabilityInstances was a good enough hint to look from a different angle

belisarius

@R.M Oh that one!

I couldn't find the thing

sorry

R.M

10

A: Build a refined grid based on intersecting line

This is my implementation using Graphics primitives and rules. Here's the final result; the implementation details and edge cases follow. 1. General approach First, we start with a single square and build up a test grid: square = Polygon[{{0, 0}, {1, 0}, {1, 1}, {0, 1}}]; grid = Graphics[{Ed...

section 3 in that one

belisarius

11:57 PM

let me see

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