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Jan
16
comment Plotting in the “Manipulate” function - simple coding
By the way, "concentric" means having the same centre, which your circles don't. I suggest choosing a different terminology :-)
Jan
12
comment How to make a drop-shadow for Graphics3D objects
@MichaelE2, many thanks for the improved initialisation code - I just couldn't figure out how to get it right.
Jan
7
comment How can I get an approximate contour plot from a 3D plot?
Is there a reason not to use ContourShading -> None to remove the polygons?
Jan
7
comment Why x = x doesn't cause an infinite loop, but f[x_] := f[x] does?
@Rojo, interestingly p:f[x_] := p does not loop
Jan
4
comment How can I make my output to be added to an existing list?
+1 but note that Mod is Listable so there's no need to map it: Outer[Plus, v, v, 1] ~Flatten~ 1 ~Mod~ 2
Dec
28
comment Deleting powers of a common prime except the highest one from a list with further only primes
@Mr.Wizard, nice. Your strip3 is what I would use.
Dec
28
comment How many Christmas gifts?
@bills, it would be an interesting challenge, but probably great fun to play with once it was done!
Dec
28
comment Deleting powers of a common prime except the highest one from a list with further only primes
@Rombert, I've added a version using more familiar notation.
Dec
28
comment Deleting powers of a common prime except the highest one from a list with further only primes
@Mr.Wizard, thank you - I think "trounced" is an exaggeration though! - as you've pointed out the code may be concise but the algorithm is inefficient for large imax.
Dec
24
comment How many Christmas gifts?
@belisarius, I was tempted to try and make it syntactically correct but a) it was too difficult and b) I had wasted too much time on it already!
Dec
21
comment Code performance problem
@rm-rf, well an image is a perfectly valid Mathematica expression...
Dec
20
comment Any ideas on how to use the Region` context?
Great find by the way. I wish we could get documentation for some of the useful stuff in these hidden-away packages.
Dec
20
comment Any ideas on how to use the Region` context?
@belisarius, it's in the definition for Region`BoundedParametrization
Dec
20
comment Any ideas on how to use the Region` context?
Check this: Region`RegionProperty[Polygon[{{1, 0}, {0, 1}, {2, 3}}], {x, y}, "FastDescription"]
Dec
20
comment How to create effect like Van Gogh's stroke brush?
@Peltio, I think one would need to segment the different parts of the image like shrx did. It might even be possible to measure the colours in each component and create the image entirely from coloured brush strokes.
Dec
19
comment How to create effect like Van Gogh's stroke brush?
@cormullion, I wondered if ListLineIntegralConvolutionPlot might help with texturing, but it's so slow! I decided to just draw some straight lines with plain old Line primitives and it came out quite nicely.
Dec
19
comment Determinant of a random matrix consisting of integers
Looking at your first attempt, some of the problems are: N is undefined (also N is a built-in function), Mi is undefined, d is undefined. Drop[Mi, {1, 1}, {1, 1}][[1, 1]] is a very long-winded way to do Mi[[2, 2]]. Return is unnecessary (just put d as the last expression in the module).
Dec
18
comment Maple like collect command in Mathematica
@highsciguy, Collect takes a third argument which is a function to be applied to each coefficient.
Dec
18
comment Deleting elements on a list by the first element of another list
@Jotasmall, yes in this example a becomes the expression Alternatives[2, 9] which is a pattern that matches either 2 or 9.
Dec
18
comment Loop function over list
@Öskå, or maybe just 1/Ratios@list