Wolfram Mathematica

5:13 AM

Is someone able help with this answer here? I cannot understand why answerer is not reciting. I am trying to pick data by two keys. Is this the way to do it? I tested his answer and I am getting totally different values than expected.

P. Fonseca

6:47 AM

By the way, working with 3d data seems to be

a necessity in the near future: handheld scanners on tablets and phones, 3d printing, etc

Wr blogs on 3d printing, and all the new function on geometry, meshing, etc, are well aligned with the very close need to be able to treat 3d data as we deal with photos nowadays... I'm really hoping for insteresting developments on future versions

of mathematica.

automatic surface reconstruction of 3d point cloud videos, etc, etc... A topic that is both interesting for future owners of phones with scanning capability, with amateur mathematica licenses, and of professional engineers, on a lot of fields...

hftf

8:35 AM

Is this spam? I'm not sure mathematica.stackexchange.com/users/22022/…

rm -rf

@hftf What about that user?

hftf

Most of the activity looks like suggested revisions that are not useful

I noticed a ton of ancient questions getting necro'd on the front page and

they all seemed to be from the same person

rm -rf

"suggested revisions not useful" != spam

I agree that the edits are probably too minor and not worth it, but new users do want to try and do things around the site to either poke around and become familiar with the site and/or to get some points here and there. Perhaps you could leave him a friendly comment telling him that his effort (and the reviewers') might be better spent on posts that need more cleanup.

hftf

Maybe we have different definitions of 'spam' … to me, high volume of non-useful edits (especially stuffing posts with links) fits my definition of spam

e.g. meta.stackexchange.com/questions/218095/…

rm -rf

8:59 AM

eh? Isn't that a bit over-reaching? The guy has been on the site for just 2 days, has asked 2 decent questions and has shown a willingness to contribute by editing. The right thing to do would be welcome him and thank him for his edits and at the same time, also educate him about not flooding the homepage and being more substantial in his edits.

hftf

9:54 AM

@rm-rf fair enough.

hhh

1:04 PM

Can someone help in importing files with headers like R's read.table command here?

(There must be some ready command for this, I am very surpirsed if there is no tool for this -- instead users must waste their time to external tools or tedious text/stream processing hacks)

I cannot understand why Mathematica users are so inactive, I really cannot see how to ignite some enthusiasm -- having no enthusiasm kills any activity :/

Leonid Shifrin

1:18 PM

@hhh If you want a quick solution, why not use RLink and R's read.table directly via RLink?

hhh

Good idea, I did not know that -- I will give it a try :D

Leonid Shifrin

@hhh You might need to write some code to translate the output of REvaluate into the form you want, but it will surely be easier than implementing a robust R-style solution directly in Mathematica.

hhh

(yeah I am always worried with this kind of tools, always trying to find a robust native solution -- too often people waste time to tedious string/stream processing when language has builtin elegant solutions for data with headers that helps their importing a lot with ignore options and identifier specification)

Leonid Shifrin

@hhh Well, RLink was built exactly to make it easy to use R's functionality without working with files, streams, etc. It may have an overhead, but that isn't always critical.

hhh

Do you have some MVE that demostrates it?

Leonid Shifrin

1:27 PM

@hhh Sorry, what's MVE?

Minimal ... example?

hhh

(I did all processing already in Vim/AWK, feeling too lazy to use new tool just now. Yes small minimal example that you have used)

Leonid Shifrin

I used to have one somewhere. Will see now if I can dig that quickly.

Murta

1:48 PM

@P.Fonseca Hi!..

Leonid Shifrin

Here is a basic example (you'll need to work more on the headers, on R side)

file = URLSave["http://samplecsvs.s3.amazonaws.com/TechCrunchcontinentalUSA.csv"];

Needs["RLink`"]
InstallR[];
RSet["testfile", file];
REvaluate["testdata <- read.table(testfile, header=TRUE)"]

gtg now, see you later.

hhh

Thank you, will check it :)

Yves Klett

3:09 PM

@LeonidShifrin I like the implied transsylvanian rendering: "children of zer night - listen to zer minimum vorking example" :D

ShutaoTang

I know there is a built-in function to implement the calculation of $ln(A)$, where $A$ is a matrix. However, I didn't find it. Can someone help me?

blochwave

3:45 PM

@ShutaoTang Is it reference.wolfram.com/language/ref/MatrixLog.html

MatrixLog[A]?

Leonid Shifrin

@hhh Obviously, URLSave didn't work for you. Not sure why, but this has nothing to do with RLink. Replace that with any custom csv file you might have on disk, and try again.

ShutaoTang

@blochwave,OK, got it. Thanks a lot:-)

Öskå

Don't forget rosetta.esa.int guys :D

ShutaoTang

@blochwave, BTW, for the arbitary function $ f $, not $ln$, rather than $sin, cos, \sqrt$ etc, is there relant built-in function ?

@blochwave, I caught it now. MatrixFunction[func,mat]

Yves Klett

4:04 PM

@Öskå touchdown :D

Öskå

@YvesKlett A very expensive touchdown :P

Yves Klett

@Öskå hmmm...

Öskå

Now it's time for them to party party

Yves Klett

@Öskå not sure, it´s so silent all of a sudden... ah, the suspense.

Öskå

@YvesKlett The lady seems happy :P

Yves Klett

4:09 PM

yup, back to party.

.... and a wild mixture of european English accents :D

Öskå

ahah yes, french incoming, going to get worse and worse :P

It has "landeud"

2

Yves Klett

@Öskå Sis is a greut ekspirience!

Öskå

@YvesKlett I just hope I don't sound like him.. :(

Yves Klett

Oh, dear, here comes the German.

@Öskå impeccable.

Öskå

Great, I don't speak German.

Yves Klett

4:16 PM

Good thing Darmstadt is not being translated literally.

now all of a sudden all the politicians put their faces into the camera.

Öskå

Yep, politicians all over the live now, zzZzzzz. I want the hoody guy back!

Yves Klett

It is somewhat disgusting. Rather show the data feed.

Öskå

Like the ESA boss said, "we did nothing"

Or more like "oui deed noting"

Yves Klett

@Öskå lol - he was sincere at least.

And now for Switzerland...

hhh

@LeonidShifrin I moved it here to process it so easier to manage.

Öskå

4:23 PM

Hoody guy > tie guys

Yves Klett

@Öskå your phonetic spelling skills are outstanding. Don´t stop.

Öskå

@YvesKlett I tried my best thank you :P

Yves Klett

@Öskå will have to tune out until the speechifying is over :(

+1 for the hoodie guy. Delete as duplicate for the ties.

Öskå

mhm.., that might be a good idea :) At least the DLR boss doesn't have a tie :P

Öskå

4:43 PM

@YvesKlett Right, so it's not anchored. Maybe it's flying around in space already..

Yves Klett

@Öskå oh, I did not follow - landed or not?

Öskå

Landed but not problem with the anchor apparently..

Szabolcs

Does anyone know what syntax highlighter GitHub uses at the moment? I thought they use Pygments. But Mathematica is highlighted fine on Github while Pygments's demo fails miserably on even simple packages.

Meta

5:42 PM

5

Q: A new tag for MMA or list of published articles which used Mathematica

I can imagine that many of the users of this website are PhD students in various research fields. I would like to have a list of published articles which used MMA to get their results or used MMA to plot their data. It would be good to have such a list ordered by research field category. I don't ...

discussion

hhh

6:16 PM

What is the command just to add a line connecting all points in a plot? I use listplot but it looks bad...

Jacob Akkerboom

@hhh probably not what you want, but it sounds like you are asking for setting the option Joined -> True (of ListPlot)

hhh

@JacobAkkerboom precisely what I wanted, thank you. My stupid idea but I am careful to see the points better.

Jacob Akkerboom

@hhh You're welcome :)

hhh

6:34 PM

Can someone help me to do the assignment?

data = Import[
"https://dl.dropboxusercontent.com/u/96742826/Mathematica/henris_\
data_s3.csv"];
vnames = Transpose[data[[{1, 2}]]];
Table[vdata[vnames[[i]]] =
DeleteCases[Drop[Map[Quiet[Check[Part[#, i], Null]] &, data], 4],
Null], {i, Length[vnames]}];
FOPR = Select[vnames, MemberQ[StringMatchQ[#, "*FOPR"], True] &];

vdata[{"FOPR", ""}]
vdata[{"FOPR", ""}][[87]] = 5000(*making the outlier smaller*);
vdata[{"FOPR", ""}]

ListPlot[Log[vdata[{"FOPR", ""}]], PlotLegends -> "FOPR"]
ListPlot[vdata[{"FOPR", ""}], PlotLegends -> "FOPR", Joined -> True]

I cannot understand why "vdata[{"FOPR", ""}][[87]] = 5000(making the outlier smaller);" does not work.

(I am trying to remove an outlier, it makes the rest of the plot totally unvisible)

Sjoerd C. de Vries

7:06 PM

Just adjust PlotRange

hhh

@SjoerdC.deVries That is correct, thank you. I feel that I cannot do anymore simple things when you need to think too many things XD

Well as a group, I find it more motivating :D

(I cannot still understand why the assignment did not work -- even though bad idea -- well I will leave it there as an unsolved puzzle)

START={{"K3_INJ", "GOIT"}, {"L1_INJ", "GOIT"}, {"K3_INJ", "GWIT"},{"L1_INJ", "GWIT"}, {"K3_INJ", "GGIT"}, {"L1_INJ", "GGIT"}, {"K3_INJ", "GVIT"}, {"L1_INJ", "GVIT"}}
GOAL={"K3_INJGOIT", "L1_INJGOIT", "K3_INJ", "GWIT", "L1_INJGWIT", "K3_INJGGIT", "L1_INJ", "GGIT", "K3_INJGVIT", "L1_INJGVIT"}

Table[StringJoin[a, b], {{a, b}, START}]

I am trying to get into GOAL from START?

HA! I find the solution by opening my mouth :D

Table[StringJoin[i[[1]], i[[2]]], {i, InjectionsIT}]

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