Reputation
49,984
Next tag badge:
247/100 score
19/20 answers
Badges
6 79 194
Newest
 Enlightened
Impact
~667k people reached

Jan
20
comment How to delete more than one (specific) elements in a list
@soandos, a||c is a perfectly legitimate pattern. DeleteCases treats it just like any other pattern, e.g. DeleteCases[{a || c, a && c}, a || c]
Jan
18
comment Can a System symbol spontaneously leak into a Global namespace?
I can reproduce the error with Mathematica 10.0.2 on Windows 7. It appears that the embedded stylesheet contains $CellContext`ParentList as a spurious entry in the InputAutoReplacements list for the style cells StandardForm and TraditionalForm in the FormatType Styles section. Removing these makes the problem go away, as does changing the stylesheet to something else.
Jan
17
comment Creating a right hand in graphics3d to illustrate the right hand rule
You could probably find a 3D model online, or is that not acceptable for your application? e.g. google.co.uk/#q=thumbs+up+3d+model+free
Jan
16
comment Partitioning with constraints on subsets
This is fantastic. It'll take me a while to work through the code and understand the algorithm! The speed is remarkable, 4 times faster than a reworked version of Martin's code. Thanks very much.
Jan
16
comment Partitioning with constraints on subsets
This is great, thanks. Just the sort of thing I was hoping for. It seems a fraction quicker if we sort the parts to put the longest ones first: parts = Reverse@SortBy[parts, Length] - I think this reduces the number of calls to f. There is also a slight gain from using Select instead of Cases in f.
Jan
14
comment Mapping Contour Plot onto ListPlot3D (or by using color variations)
You have not defined contours or gs5Matrix5. Please make sure that your code can be copied from the question into a fresh Mathematica session and produce the plot.
Jan
12
comment ListPlot3D keeps crashing
@yashar, ListPlot3D will give you a surface rather than 15 separate curves. Why not stick with ListPointPlot3D but only plot every 20th data point?
Jan
9
comment Computation time depends on the matrix elements!
Yes exactly that.
Jan
9
comment Computation time depends on the matrix elements!
Check PackedArrayQ[First@matrix] and PackedArrayQ[First@matrix2]
Jan
8
comment Extracting parts of a list subject to a condition
The question is not completely clear (for a start you have triplets {x,y,z} where y is actually x...) Are you just looking for the triplet with the most negative value of z?
Jan
7
comment After definite integration the result is still integration variable dependent!
10.0.2 gives the same result as 10.0.1
Jan
5
comment Calculating sum
The most obvious issue with your code is that you are assigning values to mm1 and mm2 and then trying to use them symbolically. Why not use different symbols in the definition of xxm?
Jan
3
comment What is the most convenient way to read definitions of in-memory symbols when we don't have the source files? (Spelunking tools)
@VladimirReshetnikov, thanks for the notification. There are a few similar examples though I never got around to debugging it. If you come up with a workaround please let me know.
Dec
30
comment How to prevent simplification?
I'm sure this is a duplicate but I can't find the previous question.
Dec
30
comment Pattern Matching in Lists
This should be fairly easy, but anyone wanting to help you is first faced with the boring task of generating a suitable dataset to test with. If you include an example dataset in the question (say a dozen rows or so) you will be much more likely to get an answer.
Dec
28
comment RegionPlot of an area inside a polar plot (or its equivalent parametric plot)
I think ImplicitRegion[{2 Pi < Sqrt[x^2 + y^2] - ArcTan[x, y] < 4 Pi, x > 0, y > 0}, {x, y}] should give the region you want, but it doesn't seem to work.
Dec
26
comment How to assemble and disassemble a function into steps
I tried to implement a part of this some time ago, a button which would break apart a CompoundExpression into separate input cells and another to reverse the process. I seem to have lost the notebook though. I do recall that I was never really happy with it and decided that it was easier just to use the divide and merge cells keyboard shortcuts.
Dec
18
comment Speed up calculation
@belisarius, the pixels injected into OP's superImg increase in value as the image list is stepped through. So the final value in any pixel is always the maximum.
Dec
17
comment Better answer to Santa's riddle about sum of a number's divisors?
@Apo, x matches a Sequence in that pattern, so Times[1, x] splices the sequence into Times, ie it gives the product of the elements in x. It's a nice trick when you're playing golf but probably best avoided in code that you might want to read again one day...
Dec
17
comment My code does not give the same results on mathematica 9 and 10
I get the same as @Kuba - no difference between versions 9 and 10.