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Sjoerd C. de Vries
Sjoerd C. de Vries
6:13 AM
A whole sring of lazy homework posters lately. Perhaps time to review our homework policy?
 
halirutan
halirutan
@SjoerdC.deVries You are speaking of the r[t] exercise, right?
 
 
6 hours later…
halirutan
halirutan
12:00 PM
@rm-rf You around? [This question] has one close vote. Can you see the close reason which was given?
 
halirutan
halirutan
12:50 PM
 
Pinguin Dirk
Pinguin Dirk
1:16 PM
@halirutan: seems like "out of scope for this site" (just following the blue "1" there)
 
rm -rf
rm -rf
2:13 PM
@halirutan Yeah, what Pinguin said.
 
halirutan
halirutan
@PinguinDirk @rm-rf Thank. Stupid me should have seen this.
 
kirma
kirma
2:57 PM
TransformedDistribution::nnbprm: The valid numeric parameters of distribution ... are expected. Use DistributionParameterAssumptions to obtain the parameter assumptions.
I wonder what's the factor that makes RandomVariate barf this way with some TransformedDistributions, and not with some others. All for which DistributionParameterAssumptions return True.
 
 
2 hours later…
Pinguin Dirk
Pinguin Dirk
4:37 PM
fyi: in the following question, I am having some troubles understanding what she wants, see comments below my answer. Maybe somebody else can see where this is heading, thanks: mathematica.stackexchange.com/questions/33081/…
 
Calle
Calle
4:56 PM
@PinguinDirk I think your most recent comment is as good an answer as anyone can provide, I don't think anyone can understands what she's saying.
 
Pinguin Dirk
Pinguin Dirk
@Calle: unless you do speak spanish :)
but thanks for checking, my english isn't that great either (so I figured it could be my mistake)
 
 
3 hours later…
Sjoerd C. de Vries
Sjoerd C. de Vries
7:53 PM
@halirutan Yes, those four, but also this , this, and others.
 
 
1 hour later…
Calle
Calle
9:01 PM
Pretend for a second that RandomReal didn't have a second argument. What would be the best way of creating a list of 10 RandomReal[] all executed separately? The best I can find: ReleaseHold[ConstantArray[Hold[RandomReal[]], 10]]
Also RandomReal[] /@ Range[10] but it's not semantic. I would like something like ConstantArray or Array without giving it an argument.
 
Michael Hale
Michael Hale
Table[RandomReal[], {10}]?
 
Calle
Calle
@MichaelHale Yes, that's better. Why I didn't think about that one myself I don't know.
 
Michael Hale
Michael Hale
There are lots of functions. I still forget about some of them.
 
halirutan
halirutan
@Calle What about
Array[RandomReal, 10]
 
Calle
Calle
@halirutan I thought about that one but it doesn't work for me since I'm not really working with RandomReal. It will just return customfunc[1], customfunc[2] etc. Only customfunc[] will return a value.
 
halirutan
halirutan
9:14 PM
@Calle ihh.. forget about my suggestion
It has to be
Array[RandomReal[] &, 10]
@Calle And the above works for your customfunc too.
 
Calle
Calle
@halirutan Yup.
 
halirutan
halirutan
Another function I have never seen until now: BlockRandom
 
Calle
Calle
Me neither, takes a lifetime to go through them all. :)
 
halirutan
halirutan
@Calle This was the advantage of having a printed Mathematica Book. You could sit down on an evening and just skim through all pages and visit every possible bit.
 
rm -rf
rm -rf
@halirutan I've used it a few times, but it looks like J.M. loves that function :)
 
halirutan
halirutan
9:28 PM
@rm-rf Everyone has his own pretty princess.
 
rm -rf
rm -rf
@halirutan Hehe, yes... I like Composition
 
drN
drN
How do I draw a vector field of a parabolic velocity profile as in http://goo.gl/2bpTCM? I tried `\[Mu] = 0.002;
R0 = 0.1;
dpdz = 13;
VectorPlot[
-(R0^2/(4 \[Mu]) ) (dpdz)[1 - (x/R0)^2] + 0*y,
{x, 0, 0.1},
{y, 0, 1}
]`, but obviously my thinking if flawed...
 
halirutan
halirutan
@drN First, if you have more than one line of code, post it as separate message here and click the button fixed font on the right. 
\[Mu] = 0.002;
R0 = 0.1;
dpdz = 13;
VectorPlot[
-(R0^2/(4 \[Mu]) ) (dpdz)[1 - (x/R0)^2] + 0*y,
{x, 0, 0.1},
{y, 0, 1}
]
@drN Secondly, what is this: (dpdz)[1 - (x/R0)^2]?
 
rm -rf
rm -rf
@drN Your syntax is incorrect for VectorPlot.
 
halirutan
halirutan
dpdz is not a function. It is a number. You cannot call dpdz[...]
 

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