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 Mar 22 comment Learning the Wolfram Language ‘from the bottom up’ The book by Wagner is good for this. Also, if you know Lisp well, it's probably better not to think of mma as Lisp with pattern matching. It feels very different to write mma because the evaluation is done very differently. Or at least, it feels so to me; I only know Lisp superficially. Dec 22 comment Can Mathematica run of the new 2015 MacBook? I run it all the time on a Mid-2011 Macbook Air. It evens runs on a Raspberry Pi. The Macbook is a lot faster than my MBA so it'll be OK. Dec 17 comment Phase space 3D diagram It would help if you defined what you meant by a "diagram". Oct 25 comment Stochastic Schrödinger Equation Well start small. Do you know how to write the code for n=1? If not, your question is actually about solving SDEs in general. Sep 1 comment Does Mathematica support Laguerre Polynomials of Matrix Argument? @belisarius nah I'm on holidays. Why don't you go ahead and do it? Jun 5 comment NDSolve break condition @Ian excellent, up voted. Happy to serve as a guinea pig. Apr 27 comment Finding adjacency matrix of a Mathematica's in-built graph? Dodecahedral is a symbol, not a graph. You want this: d = GraphData["DodecahedralGraph"]; AdjacencyMatrix[d], I think. Feb 28 comment How to define a function something like f[u_[x_]] := x, but defining a function that takes as a second argument the derivative of the first is more involved. Jan 31 comment Does Mathematica support Laguerre Polynomials of Matrix Argument? So operationally, you can think of MatrixFunction as taking a scalar function as the first arg, finding its series expansion, then using that to turn it into a matrix function and finally applying that to the second arg. If the second arg can eg be diagonalised via an orthogonal transformation, all you'd need to do do the transformation, apply a polynomial to the eigenvals and undo the transformation. Jan 31 comment Does Mathematica support Laguerre Polynomials of Matrix Argument? Oops you're right, LaguerreL is Listable so it just threads. OK, this does what you want I think: m = # + Transpose@# &@RandomReal[{-1, 1}, {10, 10}]; MatrixFunction[LaguerreL[3.2, #] &, m] (the idea is that MatrixFunction takes a scalar fn as the first arg, turns it into a matrix function and applies it to the second argument). Unless you actually do want a scalar as the output but then you need to explain how you want to get it. Jan 30 comment Does Mathematica support Laguerre Polynomials of Matrix Argument? it produces a 10 by 10 matrix of elements drawn from a uniform random distribution and then adds it to its transpose. I just wanted a symmetric matrix. Jan 30 comment Does Mathematica support Laguerre Polynomials of Matrix Argument? Apparently yes, eg m = # + Transpose@# &@RandomReal[{-1, 1}, {10, 10}]; LaguerreL[3.2, m] seems to work. In general you could also use MatrixFunction for this sort of thing. Jan 20 comment Why is (-1.)^2. a complex number @xslittlegrass I see. No idea then. Jan 20 comment Why is (-1.)^2. a complex number Look: Plot[{Re@#, Im@#} &@((-1)^x), {x, 1.5, 2.5}] Dec 16 comment Can't type in notebook in version 10 The same thing happened to me a couple of times (also on OS X). Quitting Mathematica and restarting it fixed it both times. Interestingly, when I quit, it put up a dialog to save a few of the notebooks, and there I could interact with it (to click on yes or no). Very strange. Aug 29 comment Integral of x^p Oh right that's why it doesn't work in mathematica. Oops, pattern recognised the wrong thing, I'm an idiot sorry. Aug 29 comment Integral of x^p Actually the log is recovered in the limit. It's just that mathematica doesn't recover it correctly. Aug 29 comment Integral of x^p Well, $\lim_{p\rightarrow -1} \frac{x^{p+1}}{p+1}=\ln(x)$. Not that mathematica knows this, though (try Limit[x^(1 + p)/(1 + p), p -> -1]) Aug 27 comment Numerical error in Mathieu functions Mathematica doesn't like Mathieu functions Aug 23 comment ToExpression from commandline I think it is a bug, in the sense that eg Plot[Sin[x],{x,-5,5}] doesn't cause mma to hang. So, while I agree that the fact that it fails is not a bug, that it hangs seems to be. Or am I missing something?