Newest Questions
11,827 questions
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In variational multiscale method for finite element method, how we store the fine-scale solutions?
In paper "Variational multi-scale finite element solution of the compressible Navier-Stokes equations", the author solve the fine scale solutions, but the fine scale solutions should vanish ...
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AMD Epyc F or X variant for MODFLOW?
I'm trying to choose a processor type for an HPC cluster for calculations with MODFLOW 6 (extended version). I'm looking at the F and X variants of AMD Epyc processors. The F variant has a higher ...
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53
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Help implementing the Hessenberg QR algorithm using the Keras Ops API
I am trying to implement the Complex and Real Schur Decompositions using only the Keras Ops API, so I can utilize it to impose some eigenvalue constraints on a weight matrix. I am also using the JAX ...
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3
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Solve Projection Problem with Linear Equality and Box Constraints
Solve the following problem:
$$
\begin{alignat*}{3}
\arg \min_{ \boldsymbol{x} } & \quad & \frac{1}{2} \left\| \boldsymbol{x} - \boldsymbol{y} \right\|_{2}^{2} \\
\text{subject to} & \quad ...
3
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1
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M2M in python using SciPy.sph_harm_y
I’m implementing a 3D Laplace Fast Multipole Method in Python and I’m trying to validate my P2M, potential evaluation, and M2M steps against direct summation. P2M + evaluation agree with direct ...
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198
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Numerical Simulation of Path Integral
I'm trying to code the path integral simulation described in this article. I followed all the instructions, but no matter how hard I try, my program won't work. Could someone please explain what I am ...
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46
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What does the k and l in top-k and bottom-l usually stand for?
I've seen a lot of papers with the terms top-k, bottom-l, avg-k, etc e.g. in this paper. Is there a usual meaning for the k and l that I'm unaware of? Maybe I didn't pay due attention during ...
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What are the current best practices for reproducibility when simulations depend on chaotic systems?
I’m running computational fluid dynamics simulations where small perturbations lead to divergent trajectories (chaotic systems). Even with fixed seeds, compiler differences and rounding lead to ...
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59
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More accurate ways to approximate a Finite Fourier Sine Transform?
I'm reading through this research paper, and from section 2, I have deduced that the Finite Fourier Sine Transform along $0\le x\le L_x$ is formulated as
$$F(m) = \frac{2}{L_x}\int_0^{L_x} f(x) \sin\...
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450
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Relativistic correction when integrating equations of motion for charged particles in static electromagnetic fields?
I'm numerically integrating electron trajectories through a combination of static electric and magnetic fields.
The classical equations of motion are trivial, but since kinetic energy may reach 20 keV ...
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Is SUPG/VMS very easy to diverge at flow region that transitions from hypersonic flow to subsonic flow happens?
I am coding with FEnicsx by using variational multiscale method and add an extra shock capturing method, about a high pressure gas ball(1cm radius with pressure 65 atm and 1400K), in the initial case, ...
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Force oscillations during vc-relax of ZnCu₂SnS₄ with quantum espresso
I am running a vc-relax calculation in Quantum ESPRESSO for ZnCu₂SnS₄.
Cutoff energy: 75 Ry
k-point mesh: 6×6×6
SCF converges well (total SCF corrections ~1e-5 Ry)
Issue:
Total forces oscillate ...
4
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1
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128
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How do large-scale simulations maintain numerical stability when chaotic systems amplify rounding errors?
Chaotic systems like weather models are extremely sensitive to initial conditions, and computers can only store finite precision. What algorithms or statistical techniques are used to keep results ...
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Oscillations in 1D compressible Navier–Stokes simulation
I am currently struggling with the implementation of the compressible Navier–Stokes equations in my research work. To simplify the problem as much as possible, I reformulated it as a textbook-like ...
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Does the Aubin-Nitsche trick apply for time-dependent PDEs?
I have the occasion to be reviewing some of the "basics" of the finite element method. In particular, I am interested in several technical details related to the combination of the FEM with ...