2.20.1 Top new questions this week

2.20.1.1 Reveal the formal PDE of FiniteElement

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225711

When FiniteElement method is used, the differential equations will first be transformed to certain standard form (named as formal PDE in recent FEM document), and it turns out to be critical to check ...

asked by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 11 votes

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

2.20.1.2 Drag and lift force acting on an airfoil

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225928

To calculate force acting on an airfoil we can use FEM with version 12 and over. Here we show an example with NACA2415. First we calculate mesh and potential flow:

ClearAll[NACA2415]; 
NACA2415[{m_,  ...

asked by Alex Trounev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58388 9 votes

answered by user21 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18437 6 votes

2.20.1.3 When is a symbol a Symbol? Is there an easy mathematica way to test if an object is a symbol sort of like a SymbolQ?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225811

Yes I know there is no built in native function called SymbolQ (but JavaScript does). However could one be simulated to work for most cases? I often rely

on objectName[symbol] and makeRuleRow[symbol]  ...

asked by Jules Manson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=37721 9 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 8 votes

2.20.1.4 Using Regular Expression

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225910

sample2 = "this is a test to find whether pi works for other words or not as well pi pi pi potatpi pineapple pi-neapple";

so sample2 is a string, and I want to search the word/substring ...

asked by Aryan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73776 8 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 9 votes

2.20.1.5 Changing the color of the animate box

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225941

Is there a way to change the coloring of the boxes that are generated by Animate or Manipulate? The color of what is gray by default.

Animate[ArrayPlot[CellularAutomaton[n, {{1}, 0}, {40, All}]], {n,  ...

asked by thinkingdude https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73139 8 votes

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

2.20.1.6 Bad linear fit for simple data

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225985

I have some data :

data={{1.01074, 0.964488}, {1.08552, 0.993067}, {1.07907, 
  1.01836}, {1.0477, 1.03695}, {1.07717, 1.07973}, {1.10243, 
  1.08195}, {1.12669, 1.09112}, {1.09405, 1.09319},  ...

asked by J.A https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58104 7 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 12 votes

2.20.1.7 How to use each replacement only once in a list of replacements

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225929

I have a list of replacements and some list they are acting on. However, some RHS of the replacements rules are identical (the LHS is not). I want to use those rules one after another (perhaps cycling ...

asked by Kvothe https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45020 7 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 5 votes