8.19.1 Top new questions this week

8.19.1.1 Is it possible to use the DGEEV and DSYEV LAPACK subroutines in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=269061

Here is my problem: I'm diagonalizing some matrices using  Eigensystem[]  to obtain eigenvalues and eigenvectors and I'm diagonalizing the same matrices using a ... 
[matrix] [linear-algebra] [fortran]
 

asked by User3000 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=86817 Score of 14

answered by Henrik Schumacher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38178 Score of 11

8.19.1.2 Coefficients returned from CoefficientRules

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=269129

When I used an older version of Mathematica, CoefficientRules returned coefficients as entered, say x^2 +2x  -4 y + 13., it returned {{2,0}->1,{1,0}->2,{0,1}->-4,{0,0}->13.} with all ... 
[polynomials]
 

asked by kent https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58507 Score of 9

answered by Michael Seifert https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27813 Score of 7

8.19.1.3 How to multiply only a few columns of a table by some number in a compact way?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=269183

Consider a table 
 tab = Table[{i,i^2,i^3,i^5,i^0.3,i^0.7},{i,0.2,3,0.1}]; 
 
I would like to multiply the 2rd and 5rd columns by some number. This is how I do it: 
<... 
[list-manipulation]
 

asked by John Taylor https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41058 Score of 8

answered by Sjoerd Smit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=43522 Score of 13

8.19.1.4 Speeding up cross and dot products for a list of vectors

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=268999

I am working on a code where I perform dot and cross product operations on a large list of vectors multiple times. I am using MapThread to achieve this but I feel the speed of operation is not up to ... 
[performance-tuning] [vector]
 

asked by Roopayan Ghosh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=54433 Score of 8

answered by Henrik Schumacher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38178 Score of 14

8.19.1.5 Problem with a DAE and DiscreteVariables

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=269096

I am solving an DAE problem with  NDSolve . It is a physical problem related to friction forces: one mass on the X axis and another on the Y axis, linked by a bar (L=... 
[differential-equations] [equation-solving] [numerical-integration] [numerics] [bugs]
 

asked by art https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=77549 Score of 7

answered by bbgodfrey https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1063 Score of 2

8.19.1.6 Doing ArrayReshape in Mathematica doesn't give desired results

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=269015

I have an array like this for example, 
 a = ArrayReshape[Range[16], {4, 4}] 
 
\begin{align} 
\left( 
\begin{array}{cccc} 
1 & 2 & 3 & 4 \\ 
5 & 6 & ... 
[list-manipulation] [tensors]
 

asked by Galilean https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=62831 Score of 7

answered by E. Chan-López https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53427 Score of 5

8.19.1.7 How do I map a function pairwise?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=269229

Given a list of pairs: 
 data = {{a,b},{c,d},{e,f},{g,h},{i,j}} 
 
I need the moving map: 
 MapPair[F,data] 
 
 
... 
[map] [functional]
 

asked by QuantumDot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2048 Score of 6

answered by lericr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=84894 Score of 10