4.5 Tuesday, November 21, 2017

================================== 
Top new questions this week: 
==================================

[Is it possible to construct a fullform trace function] https://mathematica.stackexchange.com/questions/160184/is-it-possible-to-construct-a-fullform-trace-function

Is it possible to construct a FullFormTrace function that takes an arbitrary expression and prints a sequence (or returns a list) of the evaluation steps in full form. For instance

...

- asked by Bob Ueland (13 votes), answered by Edmund (15 votes)

—————————-

[Integrate gives wrong result for simple function] https://mathematica.stackexchange.com/questions/160278/integrate-gives-wrong-result-for-simple-function

(probably) Bug introduced in 9.0 or earlier and persisting through 11.2

It looks like this.

NIntegrate[1/(2 + Sin[x + y]), {x, 0, 2 Pi}, {y, 0, 2 Pi}] 
22.7929 
Integrate[1/(2 + Sin[x + y]), {x, 0,  ...

- asked by huotuichang (10 votes), answered by Nasser (8 votes)

—————————-

[Select the same elements from lists] https://mathematica.stackexchange.com/questions/160222/select-the-same-elements-from-lists

I need a special intersectant operation for List other than Set.

There maybe some duplicate elements, also need to count instead of merging as Intersection.

For example:

...

- asked by GalAster (10 votes), answered by jjc385 (11 votes)

—————————-

[Building a convenient package distribution system] https://mathematica.stackexchange.com/questions/160330/building-a-convenient-package-distribution-system

The PacletManager is nice, but it’s not really a low-effort system to work with.

Installing a package can be made pretty easy, but only if the location from which it is to be installed makes it so.

...

- asked by b3m2a1 (8 votes)

—————————-

[How to merge two lists with different dimensions] https://mathematica.stackexchange.com/questions/160159/how-to-merge-two-lists-with-different-dimensions

I have two list, just like

a={a1,a2,a3,a4}; 
b={b1,b2,b3,b4,b5};

I want merge them and save to excel, as they have different dimention, so I want it have the following format.

...

- asked by zongxian (7 votes), answered by Carl Woll (12 votes)

—————————-

[What is the elegant way of applying function to two lists?] https://mathematica.stackexchange.com/questions/160028/what-is-the-elegant-way-of-applying-function-to-two-lists

I am interested in finding the most concise elegant way of doing the following: We have a function fun[x1,x2] and two lists:

ls1={a1,a2,a3,a4,......} 
 
and 
 
ls2={b1,b2,b3,b4,......}

I ...

- asked by qahtah (7 votes), answered by halirutan (11 votes)

—————————-

[Legend displaying the expected number of points per unit area next to density plot] https://mathematica.stackexchange.com/questions/160193/legend-displaying-the-expected-number-of-points-per-unit-area-next-to-density-pl

I have 2d points and want to show a colored density plot of them. I also want to display a legend showing which point density (number of points per unit area) the colors in the plot represent.

Let’s ...

- asked by mrz (6 votes), answered by C. E. (7 votes)

================================== Greatest hits from previous weeks: ==================================

[Creating legends for plots with multiple lines?] https://mathematica.stackexchange.com/questions/4025/creating-legends-for-plots-with-multiple-lines

So I have a graph with multiple lists, for e.g.

data = {{1,2}, {3,4}, {3,5}, {2,3} . . .} 
 
If I then do ListLinePlot[Table[{#1,Log[b,#2]}&@@@data, {b,1,10,2}]] 
I have no way to generate a legend  ...

- asked by Eiyrioü von Kauyf (63 votes), answered by Jens (92 votes)

—————————-

[What does # mean in Mathematica?] https://mathematica.stackexchange.com/questions/19035/what-does-mean-in-mathematica

I asked Mathematica to compute the following

Solve[c (1-x)^2-x^(1/4) == 0, x] 
 
and it returned this: 
 
  x = Root[#1^8 c^4 - 8 #1^7 c^4 + 28 #1^6 c^4 - 56 #1^5 c^4 + 70 #1^4 c^4 - 56 #1^3 c^4 + 28  ...

- asked by ronanymous (21 votes), answered by Dr. belisarius (46 votes)

================================== Can you answer these? ==================================

[Convergent infinite sum fails to converge in Sum[...]] https://mathematica.stackexchange.com/questions/160280/convergent-infinite-sum-fails-to-converge-in-sum

It looks like this.

Limit[Sum[1/((2 n + 1) Pi I - x), {n, -m, m}], m -> ] 
= -(1/2) Tanh[x/2] 
 
Sum[1/((2 n + 1) Pi I - x), {n, -, }] 
Sum::div: Sum does not converge.

Turning on Regularization ...

- asked by huotuichang (1 vote)

—————————-

[Stacked BarChart with Callout] https://mathematica.stackexchange.com/questions/159945/stacked-barchart-with-callout

BarChart examples include this code :

BarChart[Table[Callout[RandomReal[{0, 1}], Unique["text"]], 2, 8], 
   BarSpacing -> 2, ChartLayout -> "Stacked"]

Its result should be :

But I can’t ...

- asked by qwerty (2 votes)

—————————-

[Possible to add a Heading for the columns in HDF5 format?] https://mathematica.stackexchange.com/questions/159978/possible-to-add-a-heading-for-the-columns-in-hdf5-format

A similar post was found here, but it’s not using MMA.

A small test to export HDF5 file,

Export["test.h5", { "summary_Shoe" -> anssummary, "summary_Tie" -> anssummaryTie}]

Woks fine.

But ...

- asked by Chen Stats Yu (3 votes)