Unanswered Questions
14
votes
0answers
140 views
How does the performance of Python/Numpy array operations scale with increasing array dimensions?
How do Python/Numpy arrays scale with increasing array dimensions?
This is based on some behaviour I noticed while benchmarking Python code for this question: How to express this complicated ...
12
votes
1answer
547 views
Algorithms for a many-to-many generalized assignment problem
I can't seem to find any literature on algorithms which can be used to solve a many-to-many generalized assignment problem (GAP), i.e. models where not only can more tasks be assigned to one agent, ...
10
votes
0answers
92 views
Diagonal update of a symmetric positive definite matrix
$A$ is a $n \times n$ symmetric positive definite (SPD) sparse matrix. $G$ is a sparse diagonal matrix. $n$ is large ($n$ >10000) and the number of nonzeros in the $G$ is usually 100 ~ 1000.
$A$ has ...
9
votes
0answers
186 views
Difficulty with Spectral Method using Chebyshev Polynomials
I am having a bit of difficulty in trying to understand a paper. The paper uses spectral method to solve for an eigenvalue that comes from a system of coupled ODEs. I will write out only one equation ...
9
votes
0answers
144 views
Is there a tool out there that can generate interval extensions of Fortran (or C) functions by parsing Fortran (or C) code?
Case studies in my PhD thesis require that I have interval extensions of Fortran subroutines in CHEMKIN-II (apologies for the link; it's the best one I could find for a package no longer distributed ...
9
votes
0answers
148 views
Are there any open source inverse-based multilevel ILU implementations?
I am very impressed with the serial performance of multilevel inverse-based ILU preconditioners, particularly for heterogeneous Helmholtz, but I am surprised to not be able to find any open source ...
8
votes
0answers
60 views
Does anyone use software estimation methods in their computational science research?
At work, I essentially function as an independent consultant. For management and customers, I need to estimate the amount of time it will take to develop software as part of my computational science ...
8
votes
0answers
68 views
Specialized methods for symmetric tridiagonal generalized eigenvalue problems
I have to solve generalized eigenvalue problems $Ax = \lambda Bx$ where $A$ and $B$ are both tridiagonal, $B$ is symmetric positive definite and real, but $A$ is only complex symmetric (not definite ...
8
votes
0answers
338 views
PDE solvers for Drift-diffusion and related models
I'm trying to simulate basic semiconductor models for pedagogical purposes--starting from the Drift-diffusion model. Although I don't want to use an off-the-shelf semiconductor simulator--I'll be ...
7
votes
0answers
74 views
Solving unconstrained nonlinear optimzation problems on GPU
I am trying to solve some unconstrained nonlinear optimzation problems on GPU(CUDA).
The objective function is a smooth nonlinear function, and its gradient is relatively cheap to compute ...
7
votes
1answer
74 views
large dense low rank assignment problem
Is there a reasonably cheap method to solve the large, dense, low rank assignment problem $\max_\pi \sum_i A_{\pi i,i}$, where $\pi$ runs over all permutations.of $1:n$?
Here $A$ is an $n\times n$ ...
7
votes
0answers
78 views
Connections between Differential Forms and the second order Finite Volume Method
Reading today about the theory of differential forms, I was left impressed how much it reminded me of second order Finite Volume Method (FVM).
I'm struggling to figure out is thinking this way just ...
7
votes
2answers
142 views
Literature references for modeling current and future energy costs of floating-point operations and data transfers
I am searching for the most important literature and slide references for modeling current and future energy costs of floating-point operations and data transfers across the CPU, memory, network, and ...
7
votes
0answers
300 views
Replacing Mathematica's QuasiMonteCarlo integration in C++
I have a Mathematica program which performs some integrals in 3 or 4 dimensions using the QuasiMonteCarlo method. The problem is, it takes an annoyingly long time ...
6
votes
0answers
66 views
Energy conservation in the solution of the Helmholtz equation
This might be a silly question, but I know very little about the theoretical properties finite elements, so here goes. Suppose you were to solve the Helmholtz equation (let's say in 2D) with a ...
