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Sep
25
answered Joining ordered set of points with splines in spiral
Sep
23
answered Finding the surface area of a 3D convex hull
Sep
23
revised How to make a 3D topographic globe?
deleted 2 characters in body
Sep
22
comment Creating a foggy image
ImageAdjust[Blend[{image, Blur[image, 50]}, 0.8], -0.4]
Sep
22
comment An intuitive way to form an augmented matrix
@GregH: Please see my edit for an example of what I have in mind.
Sep
22
revised An intuitive way to form an augmented matrix
added 744 characters in body
Sep
22
comment An intuitive way to form an augmented matrix
It might make sense for your students if you point out that Mathematica generally doesn't distinguish between row and column vectors (what would be x'*A*x in Matlab is just x.a.x in Mathematica). Only in the context of ArrayFlatten does it matter, so you could define functions row[v_] := {v} and col[v_] := {#}& /@ v (and sca[x_] := {{x}}) to put things into the right "shape" for it.
Sep
22
comment An intuitive way to form an augmented matrix
Yes, it doesn't play too well with the usual way vectors are represented in Mathematica; even row vectors have to be {{1, 2, 3}} instead of just {1, 2, 3} for this to work. So it's far from a perfect solution.
Sep
22
answered An intuitive way to form an augmented matrix
Sep
22
comment ListPlot with lots of same couples of values
If you make it PointSize[Sqrt[#2]/50] then the area of the dots will be proportional to the tally, which seems more appropriate.
Sep
22
answered Need help with plotting triple data points while xy data are not regular?
Sep
22
answered ListPlot with lots of same couples of values
Sep
21
comment Need help with plotting triple data points while xy data are not regular?
"What you really need is not ListPlot3D, but a "ListParametricPlot3D", that AFAIK does not exist. So here's a very simple implementation..." I'm pretty sure the code in this link is exactly what you need. However, what you have to provide it is not three $m\times n$ matrices but an $m\times n\times 3$ matrix, which you can get via Transpose[{xcoords, ycoords, zcoords}, {3, 1, 2}].
Sep
18
comment How can I restore the old `ImageCompose` behaviour?
Well, that's certainly undesirable! Alpha compositing is supposed to be associative (i0~ImageCompose~(i1~ImageCompose~i2) should equal (i0~ImageCompose~i1)~ImageCompose~i2) and this doesn't do that. One could implement correct alpha compositing manually using ImageApply, but let's see if someone has a better way.
Sep
18
comment Solution to a T+U = E equation
For /., this answer in particular: Using the result of functions that return replacement rules.
Sep
17
comment How to plot a series using different colors depending on the y-value
Ah, that's the actual right way to do this. I keep forgetting: ColorFunction is for smooth colours, MeshShading is for flat colours. Right?
Sep
17
answered How to plot a series using different colors depending on the y-value
Sep
17
comment A question regarding “DiscretizeGraphics”
If you do RevolutionPlot3D[{2 + Cos[t], Sin[t]}, {t, Pi/2, 2 Pi}] it should be clear that in general one cannot expect a RevolutionPlot3D to describe a volumetric object. i.stack.imgur.com/SJAhk.png
Sep
17
comment How to generate a 3D terrain from a terrain-map image?
You need to plot imD[[All, All, 1]] instead.
Sep
16
comment How do I plot the images of oriented curves under complex transformation?
@Black Milk: Well, I should point out that the helper function is a little more complicated because my hyperbolas are secretly two curves each. If you want to apply $w$ to a single point $p$ you would do the slightly simpler Through@{Re, Im}@w@({1, I}.p).