m_goldberg
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42,068
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 2h comment Attempting to modify parts of a multi-level association in-place @LeonidShifrin. I view associations as being more like complex numbers than like lists in terms of mutability. Perhaps the analogy is ill-conceived, but nothing I've read has so far convinced me to discard it. 3h comment Attempting to modify parts of a multi-level association in-place @LeonidShifrin. AtomQ on a association returns True. 3h comment Attempting to modify parts of a multi-level association in-place Associations are treated as atomic under most operations and, therefore, can not be modified in-place. Your concept of an association as kind of structure as found in procedure languages is, unfortunately for you, wrong. 11h comment Why is Random faster than RandomReal? @wolfies. Well, you should consider the default generators may be different. 12h comment Low accuracy while solving a multi-variable equation numerically I believe that by using machine arithmetic to define V[r_], you force all later calculation to done with machine arithmetic. Which means that asking for more precision in FindRoot doesn't actually get you any more accuracy. The old numerics principle applies: garbage in, garbage out. 1d comment Manipulate slider freeze, and empty value in box @Cham. When I specified the ranges and increments of the controls, I was careful to assign reasonable values -- ones that the dynamic evaluator can handle. Negative frequencies cause trouble. I eliminated them. Increments of 0.001 over a range of -10 to 10 are too fine and make for updating problems. I used coarser ones. Try to work with the dynamic interface engine, not against it, and it will work for you. If you over-stress it, it will misbehave. 1d comment How to generate two group of $n$ random numbers in $U(0,1)$ such that sum of these two groups equal? I'll propose a cheap and dirty solution, generate the 1st set from RandomReal; then generate the 2nd by permuting the 1st one. Feb 5 comment ArXiv queries not working with ServiceConnect How does it help anyone (including you) to keep a question open when no one can reproduce the issue? When the problem can't be reproduce no answers are possible. Feb 4 comment ArXiv queries not working with ServiceConnect I'm voting to close this question as off-topic because the problem the user is experiencing can not be reproduced by others. Feb 4 comment ArXiv queries not working with ServiceConnect I just executed the same Documentation Center example code as you post on my system and I got a dataset containing four articles. I'm running V10.3.1 on OS X 10.10.2. Feb 4 comment Force mathematica to consider variables as real A*Exp[i*m]  isn't going to work. Did you mean A*Exp[I*m] ? Feb 4 comment How can I graph this using Mathematica You say you have the answer, which of course is a function expressing the torus centered at {5, 0, 0} with its major axis aligned to the y-axis. All you need to do is put that function into parametric form and plot it with ParametricPlot3D. I recommend the making the plot with a few options to make it look nice. ParametricPlot3D[torusF[u, v], {u, 0., 2. π}, {v, 0., 2. π}, AxesLabel -> {x, y, z}, Mesh -> Full, ViewPoint -> {35, 25, 15}], where torusF[u, v] is parametric form of the torus function. Feb 2 comment Distance between a circle and a line Unless you indicate that you are using Mathematica software to solve your problem this question is likely to be transferred to Math.SE. Feb 2 comment Distance between a circle and a line Welcome to Mathematica.SE. Are you sure you are posting on the right site? There is nothing in your question making it clear that it is concerned with Mathematica software. Feb 2 comment How can I add a checkbox to a Manipulate expression? @Cham. I know of no simple command that will make the controls in a Row behave as there were a spring spacer between them. pushing them to space out over the full width of the panel they located in. Feb 1 comment How best to simulate n-body systems in a functional way I have edited the title, but am not certain my edit is a sufficiently better description of your problem that it should stand. I you think it is not, please go back to your original title. I also tried to improve your sentence structure, but in some cases the wording was ambiguous enough that I may have made some bad changes. Please review my 'corrections' and correct them as you see fit. Feb 1 comment For Loop clarification I can not comprehend your question. What do you mean by "adjacent neighbor" and "last three polygons"? Also, why are using a for-loop at all, when only want to compute neigh[[1]]? Feb 1 comment Evaluating While Loops inside Modules The OP's while-loops loop from 1 to 4 in both loops. Jan 31 comment Need help interpreting a small block of code You should be aware that Print always returns Null, so ff = Print[KK]; CE[α, β, γ, l_, m_, n_] = ff defines certain forms of CE to be identically Null. This doesn't make a lot sense unless this has side effects on in the code surrounding the Do expression that you don't show us. Jan 31 comment Evaluating While Loops inside Modules I think f[1] should be z + z^2 + z^3 + z^4