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Feb
28
comment Finding the optimal teams ranking based on the table of match results
Are you absolutely sure you want to iterate over all 90 billion permutations? That's a lot of iterations. If I were you, I'd first ask on math.stackexchange.com whether there exists a more efficient algorithm that doesn't take superexponential time, and then implement that instead.
Feb
27
comment How to resolve the duplicate error during interpolation
I guess FindCurvePath is the key here. Very nice.
Feb
27
comment Log of a Quaternion
I've filed a bug at wolfram.com. Let's see what they say.
Feb
27
comment Log of a Quaternion
Yes, you can do qNormalized = q/Sqrt[Norm[q]] and evaluate Log[qNormalized]. Mathematically it should be $q/\|q\|$, but for some reason Mathematica defines Norm[q] to be $\|q\|^2$ instead.
Feb
27
comment Log of a Quaternion
The scalar of the log of a unit quaternion is zero. q is not a unit quaternion.
Feb
27
answered SmoothDensityHistogram with logarithmic density
Feb
26
awarded  Popular Question
Feb
25
comment Using an ellipse as a threshold for Nearest function
@Yves: I had to go to bed. I'm happy to see that Szabolcs has taken care of it. :)
Feb
25
comment Using an ellipse as a threshold for Nearest function
@Yves, bill: One could transform the data so the ellipse maps to a circle, use the standard Euclidean distance there, and transform the results back.
Feb
25
comment Generating a (random) 2-dimensional cellular network
@kirma: Only if you also constrain angles to force the polygons to be regular. Otherwise I think there is quite a bit of freedom.
Feb
24
revised Understanding Bilinear ImageResize
added 166 characters in body
Feb
24
answered Understanding Bilinear ImageResize
Feb
24
comment When running Mathematica from a Linux terminal, how can I prevent a script from terminating upon logout?
Have you considered using a terminal multiplexer like GNU Screen or tmux? Then you can keep your entire console session running after you logout.
Feb
23
comment Solving an Integral Equation Numerically
I'm pretty sure that exp(...) should be Exp[...] instead.
Feb
23
answered Why isn't my Stream code plotting multiple solution curves?
Feb
23
comment Why isn't my Stream code plotting multiple solution curves?
@rasher: That doesn't help as much as it should. It seems that Mathematica has trouble dealing with streamlines on plots that have very large or very small aspect ratios. In this case, the range of $y$ is less than a tenth of the range of $x$. Observe that if you rescale the domain and plot {1, 10 ((y/10)*(1 - y/10) - 0.2 + 0.1*Cos[2*x])} on {x, 0, 15}, {y, 0, 12}, you get the desired results.
Feb
21
comment SmoothDensityHistogram with logarithmic density
It's just choosing a weird plot range because the density is nearly 0 (so the log tends to $-\infty$) in most of the plot. With for example PlotRange -> {-5, Automatic} you get what you expect.
Feb
21
comment Transform an expression to remove the singularity
@bill: I suppose what I need is a FunctionReduce along the lines of TrigExpand/TrigReduce. :)
Feb
21
comment ListContourPlot3D doesn't use all points
If you make the input data just be a three-dimensional array, gauss = Table[Exp[-i^2 - j^2], {i, -2, 2, 0.1}, {j, -2, 2, 0.1}, {k, -2, 2, 0.1}], then ListContourPlot3D uses all the values, but the orientation and scaling of the axes is off. You can fix the scaling with DataRange -> {{-2, 2}, {-2, 2}, {-2, 2}}, but not sure what to do about the orientation. i.stack.imgur.com/17ozK.png
Feb
21
comment SmoothDensityHistogram with logarithmic density
ScalingFunctions -> "Log"?