================================== Top new questions this week: ==================================
[Incorrect Timing of Total] http://mathematica.stackexchange.com/questions/98453/incorrect-timing-of-total
For demonstrating how fast C-compiled functions can be, in one of my courses I use the following function for finding the sum of a list of reals:
myTotal = Compile[{{lst, _Real, 1}},Module[{s=0.}, ...
- asked by Fred Simons (17 votes), answered by ilian (12 votes)
—————————-
[Aggregation queries on lists of associations in 10.3] http://mathematica.stackexchange.com/questions/98277/aggregation-queries-on-lists-of-associations-in-10-3
Bug introduced in 10.3
Some aggregation queries applied to a list of associations (or Dataset’s with this structure) lock up the front end or crash the kernel in Version 10.3.
xx = {<|"a" -> ...
- asked by Daniel W (14 votes), answered by SquareOne (7 votes)
—————————-
[On making a graphical real-time memory usage monitor] http://mathematica.stackexchange.com/questions/98205/on-making-a-graphical-real-time-memory-usage-monitor
I’d like to make a graphical version of
Dynamic[Refresh[MemoryInUse[], UpdateInterval -> 1]] A naive implementation would be something like: miu = {}; Dynamic[Refresh[ListPlot[AppendTo[miu, ...
- asked by kjo (12 votes), answered by Karsten 7. (7 votes)
—————————-
[How to sort list of mixed types of elements with each type a specified canonical order?] http://mathematica.stackexchange.com/questions/98438/how-to-sort-list-of-mixed-types-of-elements-with-each-type-a-specified-canonical
For example, here is a list
{{1, "u"}, {6, "d"}, {3, "u"}, {4, "d"}, {2, "u"}, {5, "u"}, {3, "d"}, {1, "d"}, {4, "u"}, {2, "d"}, {5, "d"}, {6, "u"}} The default canonical order for integer is ...
- asked by matheorem (11 votes), answered by belisarius is forth (14 votes)
—————————-
[How do you concatenate matrices? And how do you make block matrices?] http://mathematica.stackexchange.com/questions/98406/how-do-you-concatenate-matrices-and-how-do-you-make-block-matrices
This is pretty trivial to do in Matlab, but I have not seen a function for it in Mathematica. Here is how you can do it with Join and Transpose. Is there an easier way to do it than this?
...
- asked by luke wendt (10 votes), answered by Taiki (12 votes)
—————————-
[Association Subtotals with Lists as Keys] http://mathematica.stackexchange.com/questions/98346/association-subtotals-with-lists-as-keys
I have the following Association:
as = <|{5, 2, 1} -> 3, {6, 1, 4} -> 9, {5, 1, 9} -> 12, {5, 2, 4} -> 6, {6, 2, 8} -> 10|>;
I want to total the values on the right side of the ...
- asked by eldo (10 votes), answered by Pillsy (13 votes)
—————————-
[get position index for all element in a list] http://mathematica.stackexchange.com/questions/98170/get-position-index-for-all-element-in-a-list
For example
mat={{a,b},{c,a,a}} How to write a function posindex that posindex[mat] will give {{a -> {1, 1}, b -> {1, 2}}, {c -> {2, 1}, a -> {2, 2}, a -> {2, 3}} And the function ...
- asked by matheorem (10 votes), answered by Michael E2 (8 votes)
================================== Greatest hits from previous weeks: ==================================
[3D surface that looks like a virus] http://mathematica.stackexchange.com/questions/74193/3d-surface-that-looks-like-a-virus
I have been recently using Mathematica for composing animations that are part of the supplementary information of my papers.
I am currently trying to build an animation that involves a viral ...
- asked by user2098 (16 votes), answered by Chris Degnen (18 votes)
—————————-
[Mathematica Minecraft] http://mathematica.stackexchange.com/questions/19669/mathematica-minecraft
Some time ago I asked myself: with all these great graphics and interactive capabilities of Mathematica, what kinds of 3D games can be implemented in it? And the answer which came to mind is ...
- asked by faleichik (131 votes), answered by faleichik (176 votes)
================================== Can you answer these? ==================================
[Triggering events based on choices made inside of system dialogs (e.g. window close)] http://mathematica.stackexchange.com/questions/98091/triggering-events-based-on-choices-made-inside-of-system-dialogs-e-g-window-cl
I’m trying to arrange for Mathematica to perform a certain action every time a notebook is saved or closed (with or without saving). The obvious way to do this would be through event handling. So, ...
- asked by Paco Jain (5 votes)
—————————-
[ListContourPlot and ListContourPlot3D use better interpolation for arrays of values than for lists of tuples (i.e. x,y,z,f[x,y,z]..] http://mathematica.stackexchange.com/questions/98145/listcontourplot-and-listcontourplot3d-use-better-interpolation-for-arrays-of-val
From reading the documentation, it seems that ListContourPlot3D should work equally well on an array versus a list of tuples,
?ListContourPlot3D ListContourPlot3D[array] generates a contour plot ...
- asked by Jason B (10 votes)
—————————-
[Size problems combining objects in a Graphics using Inset] http://mathematica.stackexchange.com/questions/98282/size-problems-combining-objects-in-a-graphics-using-inset
The Problem
I need to put together different graphics objects in a precise way inside a Graphics. Some objects are drawn directly by graphics primitives, some others are the result of calls to ...
- asked by Guido (4 votes)