1.2.1 Top new questions this week

1.2.1.1 How to make Mathematica read in CSV as fast as Python’s Pandas

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=249369

I have many big CSV files for processing in Mathematica. And each time loading them into Mathematica takes a long time. Meanwhile, it takes much less time using Pandas under Python. For example, ...

asked by sunt05 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=260 17 votes

answered by George Varnavides https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41179 9 votes

1.2.1.2 How to construct a tree from a preorder traversal

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=249256

The list t1 = {1, 2, 3, 3, 4, 4, 3, 3, 4, 3, 3, 2, 3, 4, 2, 3, 2}; might be derived from a pre-order traversal of ...

asked by High Performance Mark https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=519 8 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 13 votes

1.2.1.3 TimeSeriesShift seems broken – is there a stable workaround?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=249275

Issue 1: Certain dates shift into the same date, leading to duplicated keys, rendering the time series unusable: ...

asked by secr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=80404 7 votes

answered by Gosia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5372 0 votes

1.2.1.4 Unable to solve nonlinear PDE with NDSolve

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=249356

Lately, I’ve been trying to solve the following PDE:

\begin{equation} -v_0 |\nabla F| + {\bf f}\cdot \nabla F +D\nabla ^2F = -1 \end{equation}

inside a 2D region between two disks both centered in the ...

asked by lorenzop https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74662 5 votes

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

1.2.1.5 Sort list by a condition on parameters

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=249332

Consider the following list

list={{{0,0,0},0},{{0,0,1},a},{{0,0,-1},-a},{{1,0,1},b},{{1,0,0},-b},{{1,1,1},a+b},{{1,1,1},a-b},{{-1,0,-1},{-a-b}},{{-1,0,-1},{-a+b}}};
 

asked by jarhead https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26549 5 votes

answered by Lukas Lang https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36508 4 votes

1.2.1.6 AceFEM: Divergence in iterative procedure (Newton-Raphson) for fine meshes

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=249175

I am trying to model a problem of a nearly incompressible \(10~\rm {m} \times 2~\rm {m}\) beam with a uniformly distributed end load. The beam has a Young’s modulus of \(200~\rm {Pa}\) and a Poisson’s ratio ...

asked by DvanHuyssteen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69831 5 votes

1.2.1.7 Efficient computation of Hopf index

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=249168

I am trying to check using Mathematica the following result:

\[-\frac {1}{4\pi ^2}\int _{0}^{2\pi }\int _{0}^{2\pi }\int _{0}^{2\pi } \mathbf {F}\cdot \mathbf {A}\;dk_x dk_y dk_z=1,\quad \text {where}\]

...

asked by Hyeongmuk LIM https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=80354 5 votes

answered by Fidel I. Schaposnik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45839 4 votes