6.1.1 Top new questions this week

6.1.1.1 How to determine if two mutable data structures are the same?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218535

How can I determine if two mutable data structures (DataStructure) are truly the same? I do not mean checking if they have the same value. I mean checking if they are the same data structure, i.e.  ... 
[data-structures]
 

asked by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 15 votes

answered by ilian https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=145 14 votes

6.1.1.2 Is there official documentation for official documentation and getting help system of Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217230

Mathematica has very high quality and extensive documentation and good getting help system (? Solve as an example; there maybe are more too). Is there all including official documentation about  ... 
[documentation]
 

asked by vasili111 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=11639 14 votes

answered by WReach https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=142 11 votes

6.1.1.3 Mottled appearance of ContourPlot3D with transparency

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217226

I'm trying to make a ContourPlot3D that needs to be transparent. With transparency, however, something odd happens. 
 
With PerformanceGoal->"Speed", the colors look fine. 
 
With  ... 
[plotting] [graphics3d] [color] [rendering] [transparency]
 

asked by Peter Todd Williams https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70508 11 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

6.1.1.4 Dividing by Zero - Unexpected Result

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218539

When I divide this number by zero I get this for an answer. 
 
ans = 2345900/0 
 
 
(*  *) 
 
What is surprising is that in taking the square root, Mathematica seems to map the entire universe to some town  ... 
[bugs] [numerics] [evaluation] [splines]
 

asked by MikeY https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=47314 9 votes

6.1.1.5 How can I plot a parametric equation with ś?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217227

I want to draw a parametric equation with ś like the figure below: 
 
 
 
But I don't get the result I want when I run the following code. What can I do to get it? 
 
ParametricPlot[{x, śx^2}, {x, 0, 1}, 
... 
[plotting] [core-language]
 

asked by Please Correct GrammarMistakeshttps://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 9 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 16 votes

6.1.1.6 Mathematica numerical "error" for simple multiplication

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217205

 
 
In[71]:= 0.6*0.8048780487804877` 
 
Out[71]= 0.482927 
 
In[72]:= 0.3*0.8414634146341463` 
 
Out[72]= 0.252439 
 
In[74]:= (0.6*0.8048780487804877`) + 0.3*0.8414634146341463` 
 
Out[74]= 0.735366 
 
In[75]:=  ... 
[numerics] [syntax]
 

asked by htam_ujn https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70502 9 votes

answered by m0nhawk https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2342 8 votes

6.1.1.7 Why can't I use Inactive[D] in NDSolve?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217169

I have a 2D rectangular domain with -L/2 < x < L/2 and 0 < y < D0, which is divided into two parts, with a sinusoidal curve y == 1 +  Cos[2 Pi x/L] separating the two. 
 
I want to solve  ... 
[differential-equations] [finite-element-method] [hold]
 

asked by Physicist https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41581 8 votes

answered by user21 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18437 8 votes