| Top new questions this week: | 
| [UPDATING]  Here is a solution based on the answer proposed by professor Bangerth down below. To describe what I am trying to do, first rewrite the question into  $$\max_X\|(I-\alpha X)^{-1}X\circ AE\|… | 
| In any FEM problem involving mechanics, we try to solve the differential equation for the displacement field, $u$ given the force vector in the nodes, $F$. In industry, we often see our automobiles … | 
| I am dealing with a non-trivial Riemannian metric $H$ defined on a particular subset of Euclidean space ($E \subset \mathbb{R}^n$). I was able to show the Riemannian manifold $(E,H)$ is geodesically … | 
| Consider the following nonlinear diffusion problem,  $$  \frac{\partial u}{\partial t} = x^{-2}\frac{\partial}{\partial x}\left(x^2 u^4 \frac{\partial u}{\partial x}\right), \quad 0 < x < 1  $$  We … | 
| I’m attempting to solve a strange differential equation problem. My goal is to know if there are kinds of ODE solver packages to solve this kind of problem.  I’m solving a 1D Partial Differential … | 
| I have lots of difficulties trying to make a phase plot for the motion of the particle trapped in Lennard-Jones potential:  $$V(q)=\epsilon\left[\left(\frac{q_\mathrm{min}}{q}\right)^{12}-2\left(\frac{… | 
| A recent question in Astronomy SE Numerical Programming using odeint takes more than 17 minutes got me interested in looking closer at SciPy’s odeint.  The problem is a modified orbital mechanical … | 
| Greatest hits from previous weeks: | 
| I know that the Nitsche’s method is a very attractive methods since it allows to take into account Dirichlet type boundary conditions or contact with friction boundary conditions in a weak way without … | 
| Does anyone have recommendations on a usable, fast C++ matrix library?    What I mean by usable is the following:  Matrix objects have an intuitive interface (ex.: I can use rows and columns while … | 
| What is counterpoise correction exactly ? Can you explain when it is needed and why ? | 
| $A$ and $B$ are $n \times n$ matrices and $v$ is a vector with $n$ elements. $Av$ has $\approx 2n^2$ flops and $A+B$ has $n^2$ flops. Following this logic, $(A+B)v$ should be faster than $Av+Bv$.    Yet,… | 
| I am doing a molecular dynamics simulation. I need to assign initial velocities to the atoms. I want to assign the initial velocities which follow the Maxwell-Boltzmann distribution. How do I … | 
| This might be a question better suited for the Software Recommendations side of S.E., however I do believe that people who frequent this part of S.E. are more likely to be able to answer this question…. | 
| Related question: State of the Mac OS in Scientific Computing and HPC    A significant number of software packages in computational science are written in Fortran, and Fortran isn’t going away. A … | 
|   Can you answer these questions?								 | 
| I’m quite new to the smoothed particle hydrodynamics method, so I’m trying to find Matlab or Python code to help me understand it. Specifically, I want to know how to solve the one-dimensional … | 
| I am trying to calculate classical trajectories for a single positive ion and a single electron inside an RF trap. Therefore, I am dealing with a two-body system that possesses:    Coulomb potential … |