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12h
awarded  Nice Answer
12h
comment Syntax information “ArgumentsPattern” for function of function?
I don't think so. It must always be defined as SyntaxInformation[f] = sompatterns and somepatterns need to follow a very restricted syntax (as documented). I think that's because they're interpreted by the front end, not the kernel. This is of course just an educated guess. +1 though, interesting question.
1d
comment How does FindShortestTour work?
@Silvia Here's the link to the old docs. I wonder if the algorithms used by FindShortestTour have changed in v10.
1d
comment Having difficulty with NDSolve
If sym is the name of the symbol you're interested in then you can get information about it using ?sym. Look up Information in the docs.
2d
answered Default color for Filling in Mathematica 9
2d
comment How to tell Mathematica that certain variables are real/imaginary, integer-valued, etc
There's no general way to declare a variable as real, integer etc. Instead, some functions take an Assumptions option which affects that function. Take a look at reference.wolfram.com/language/tutorial/UsingAssumptions.html and also ComplexExpand. There can be a default for the Assumptions option through $Assumptions but it won't affect everything, only functions that know about assumptions.
2d
comment Defining an array using this specific rule
You don't need to nest two Tables and then flatten, just use two iterators in the same one.
2d
comment Defining an array using this specific rule
This seems to be a straightforward use of Table, unless I missed something ... Please take a look at it in the documentation. You'll also need Ceiling.
2d
comment How to use C language functions in Mathematica?
I believe this is a duplicate of mathematica.stackexchange.com/q/8438/12 LibraryFunctionLoad is meant to be used only with functions specifically written for LibraryLink. If you are going to use LibraryLink, you will need to create a LibraryLink-compatible wrapper for whatever you need to call. There are other methods than LibraryLink for calling C functions, all described in the thread I linked.
2d
comment Is plot polluting my context?
This only happens in v10, not v9 or v8.
2d
comment Is plot polluting my context?
What a coincidence! I reported this to WRI about 10 minutes before you posted. But I didn't realize that it was Plot that did it. I was blaming the summary boxes from InterpolatingFunction.
2d
comment Having difficulty with NDSolve
Regarding seeing every variable in the workspace: Mathematica doesn't have variables in the sense R or MATLAB has them. It has symbols. Symbols may have associated "definitions" (actually transformation rules) of various types. Sometimes this does look like variables on the surface, but it's really not the same, and this does matter (see above how the definition of z'[x] was associated with something else than z). You can get the list of symbols in the Global` context using ?Global`* and examine each one's definitions using ?sym.
2d
comment Having difficulty with NDSolve
@David You likely typed z'[x] = -y[x], which assigned to z'[x]. You expected that z'[x] would then be cleared by Clear[z]. Actually this won't clear it because we're facing a special situation here. z'[x] is a shorthand for Derivative[1][z][x] so the assignment is associated with Derivative (specifically its SubValues), not z. This is surprising to many people because Derivative is a system symbol, and system symbols can't normally be assigned to (most are Protected). Derivative is special though. So how do you clear it then? The simplest safe way is z'[x] =..
2d
comment Having difficulty with NDSolve
A note to people voting to re-open: please explain in a comment why the question should be reopened, otherwise it's unlikely to happen. People here tend to listen, just explain why ;-)
2d
comment Non-linear system of equations with a parameter
Try googling for "mathematica solve equation" then for "mathematica table". Please, before asking for others' time to solve your problem, at least show that you have tried to do it on your own first.
2d
comment Is it possible to draw really thin lines in Mathematica?
@funnypony Out of curiosity, why do you need to reproduce matplotlib's result with such fidelity? If it's really important to have the exact same output, why not just use matplotlib? Also, I guess matplotlib's output will depend on the precise rendering method and might easily change in the future.
Nov
21
awarded  Necromancer
Nov
20
comment Fitting to a power law — is there any reason to fit a line to the log of the data instead?
So to add to @KennyColnago's comment, it depends on where the data comes from and see homoscedasticity. In many applications where power laws come up, the values vary over several orders of magnitude, and so does the noise, so usually it makes a lot more sense to take the log. But it always depends on the particular application.
Nov
20
comment Fitting to a power law — is there any reason to fit a line to the log of the data instead?
This question appears to be off-topic because it is asking about numerical methods, not about how to accomplish something with Mathematica.
Nov
20
comment Fitting to a power law — is there any reason to fit a line to the log of the data instead?
This is not a Mathematica question, it's a math/statistics question, so voting to close. I suggest asking on Stats.SE. This is a very popular article on the topic, which you should take a look at. Note that the numerical results about the CDF fitting in the paper are flawed. Using the CDF actually gives pretty good results. Nevertheless, the main point stands: if you're fitting a distribution, for robust results use maximum likelihood methods.