All Questions
11,504
questions
1
vote
1
answer
89
views
How to run scipy.optimize.minimize with L-BFGS-B for maxiter (completely)
I want to run the below code for maxiter = 20001. I don't want it to stop by some default criteria.
...
0
votes
0
answers
40
views
Advanced computing on FPGA
I am an absolute beginner in the FPGA topic (so far I have only implemented a couple of simple logic gates in Verilog and simulated them in ModelSim). I studied digital electronics, logic elements, ...
- 131
0
votes
0
answers
40
views
How can I calculate ROC50 in python?
I need to calculate ROC50 for a classifier in python. The ROC50 value is defined as the AUC when the 50th true negative is found. I have tried setting the max fpr value for roc_auc_score in sklearn to ...
- 101
1
vote
0
answers
42
views
How can I apply a mixed boundary condition to a multi-material heat transfer problem using Crank-Nicolson?
I am working on a mixed material model for a melting material and need to enforce both a Dirichlet and Neumann type condition at the interface. Subject to an external surface heat flux at the top of ...
- 11
1
vote
0
answers
33
views
Imposing higher order finite difference schemes for boundary value problems on a finite interval
I have some questions. I'm going to assume everything is in 1d with a Laplacian operator. If I discretize the Laplacian operator using $p = 2a+1$ grid points with periodic boundary conditions, I ...
- 111
0
votes
1
answer
106
views
Is the NLP formalism sub-optimal for real-world problems
My home-brew optimization studies have raised yet another fundamental question. The Nonlinear Programming formalism, "minimize f(x) subject to inequality and equality constraints, and x ...
- 329
0
votes
0
answers
57
views
On Newton-Raphson Method for Single Degree of Freedom Systems
I am trying to understand the geometric interpretation of the Newton-Raphson method as used in nonlinear structural mechanics. The fundamental governing equation of nonlinear structural mechanics is ...
2
votes
0
answers
86
views
What is fastest method for finding the minimum and maximum eigenvalues of a (possibly very large) symmetric matrix?
What is the best way to find the extreme eigenvalues - in order to find the spectral radius - of a general real dense symmetric matrix?
Looking at similar questions e.g.: What's the most efficient ...
- 23
0
votes
0
answers
20
views
What is the most accurate way of computing the evaluation time of a neural network model?
I am training some neural networks in pytorch to use as an embedded surrogate model. Since I am testing various architectures, I want to compare the accuracy of each one, but I am also interested in ...
- 23
4
votes
3
answers
134
views
Is there any matlab built-in function or libraries to calculate $\frac{d(\ln A)}{dA}$?
we can first conduct spectral decomposition of an positive definite isotropic tensor $A$ and then we can define $\ln(A)$, then we can define the frechet derivative of it, but how to calculate this in ...
- 191
5
votes
3
answers
190
views
Benchmark Neural Networks on High-Dimensional Functions
For a personal project, I am interested in benchmarking certain neural network architectures in the context of high-dimensional function approximation. Specifically, I am interested in continuous, ...
- 169
4
votes
1
answer
361
views
Non-uniform Gaussian spaced vector
I am working on a Fortran code that uses a uniformly spaced grid in two directions (x,y). Which works fine, but when I need to study a certain problem with good resolution, I need to increase the ...
- 43
2
votes
1
answer
155
views
how to compute the rate of deformation gradient in finite-element context?
I am implementing hyper visco-elastic material models similar to those from Pioletti et al. see here
There, a viscous potential, e.g
$W_v = \eta [I_1-3]J_2 \quad \text{with} \quad J_2 = \mathrm{tr}(\...
- 185
0
votes
0
answers
41
views
representing firing rates of a neuron using delta functions [computational neuroscience]
I'm reading 'fundamentals of computaional neuroscience' by Thomas P. Trappenberg and was confused while reading about representing firing rates using direc delta functions.
instantaneous firing rate ...
1
vote
1
answer
191
views
Solving linear system of equations with constraints on unknowns
I would like to solve a system of linear equations $y=Uh$ for an unknown vector $h$, where I have a few constraints on some of the elements of $h$. The matrix $U$ is composed of a vector $u$ (length $...
- 35