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59 views

Should I use bestman2 or dcache CLIs (srmping, srmls, etc..)

I am fairly new to using SRM, and I am wondering if I should be using srm CLI tools (srmping, srmls, srmcp, etc..) provided by dcache, or bestman2 counter parts (srm-ping, srm-ls). I used to think ...
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1answer
72 views

How many years it would take our laptops to be as fast as the fastest super computer in 2000 [closed]

How many years it would take our laptops to be as fast as the fastest super computer in 2000 according to Moore's law?
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votes
1answer
70 views

Finding roots without knowing much about the function

Consider solving numerically for roots: $( x_0, y_0): f(x_0, y_0) = 0, g(x_0, y_0) = 0$ where you only know that f, g continuously differentiable but the theoretical differentiation is not a ...
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1answer
68 views

Particle Collision to Static paticles

I have a system of particles with equal distance with each other and another at random positions which is moving with time. I want to know: a) The method by which I can reduce the number of particles ...
0
votes
2answers
541 views

How to decrease computation time for symmetric matrices?

We all know the problem that computation time explodes when simulating systems with big matrices. I got just this problem, but I have the advantage that I know that my matrices are symmetric. My ...
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votes
1answer
529 views

Solver for large non-linear system of equations

I am curently using R package nleqslv for solving a non-linear system of equations with 300 variables. I need to scale this to the system with ~50k variables and naturally this does not scale very ...
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votes
1answer
469 views

MATLAB Newton non-linear equation

I have the following non-linear equation: where $w0=0.25,w0=0.5,w0=0.75$. I have to prove that if $k$ is a root, then also $−k$ is a root and that there exists only one $k∈(0,1)$ root, but my MATLAB ...
0
votes
1answer
414 views

Elastic LP Programming

Say I have an LP that is unfeasible and that I want to find the solution that makes it feasible without strongly violating the current constraints. What is a principled way of solving this problem, ...
0
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1answer
80 views

Rank of image intensity matrix

I've been reading a paper about using Matrix Completion for Photometric Stereo but I am having some troubles in section 2.2 trying to understand why irrespective of the number of pixels and the number ...
0
votes
2answers
282 views

Systems of nonlinear equations

Consider the nonlinear system of equations $$ (1) \quad qk^2a_1^2E^2+wna_0a_1AE+pnka_0^2a_1E+rn^2a_0^2A^2-rn^2a_0^3A^2+qk^2a_0a_1ABE-qk^2na_0^2E^2=0, $$ $$ (2) \quad nwa_1^2AE+nwa_0a_1AB+2pnka_0a_1^...
0
votes
2answers
287 views

WENO reconstruction of flux involving derivative terms

I have a set of modified compressible Euler equations that I would like to solve using a WENO method. The issue is that the modified flux function involves derivative and filtering terms and I'm not ...
0
votes
1answer
502 views

Truncated SVD implementation in Java

I need the Truncated SVD implementation in java. I need to pass a matrix of doubles and an integer value representing the rank where to filter out noise. In output i need a filtered matrix of doubles. ...
0
votes
1answer
2k views

How to detect smiles using OpenCV and IntraFace?

I have installed OpenCV and IntraFace, now the code can detect landmarks on the face, like this : Now how can I convert this to a smile detector? I have the landmark points as an array, so I should ...
0
votes
1answer
400 views

Custom CVX Functions - Overriding Errors [closed]

I have constructed a function in Matlab that is convex and increasing (qualitatively similar to an exponential function but I am hoping to avoid the successive approximation requirement of exp). In my ...
0
votes
1answer
77 views

Which version of FFTW

At the moment, I'm installing the "GADGET-2" application. In its documentation it says "Note that the MPI-capable version 2.x of FFTW is required, the new version 3 lacks MPI capability at this point. ...
0
votes
1answer
51 views

Best way of getting updates on intermediate simulation results

I will be interfacing our fluid dynamics code with an optimizer. I expect the optimization process to take 3-4 days for any decent decrease. But I will want to have a look at the intermediate results ...
0
votes
1answer
68 views

SVM Math Question

I'm studying support vector machines and came across this paper. The following equation doesn't make sense to me, especially the part with the 0 ∀i. Any help understanding the basics of SVMs? yi * (...
0
votes
1answer
305 views

How could I implement this neural network in R? [closed]

In Establishing, versus maintaining, brain function: a neurocomputational model of cortical reorganisation after injury to the immature brain, Varier et al develop a neural network model of motor ...
0
votes
1answer
753 views

Degradation Model in MATLAB

I am trying (using MATLAB) to generate the following image (from the section 4.1 Numerical Examples) of Wu Tian Chen research article 'Condition-based Maintenance Optimization Using Neural Network-...
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votes
1answer
66 views

Can I use Engineering codes like ASHRAE , NFPA and UPC in my software without permission? [closed]

Say, I want to use the UPC code Water Supply Fixture Unit tables in my software that I'm writing ... is it okay or there will be copyright issues?
0
votes
1answer
112 views

max speed <--> time discretization

I'm working on a heat diffusion problem, $$ \frac{\partial T}{\partial t}=\vec{\nabla}\cdot\left(\kappa T^{5/2}\,\vec{\nabla}T\right) $$ I know that, after discretization, the time step for the 1D ...
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votes
1answer
235 views

Implementation of the MARTINI force field

Given an input parameters for the MARTINI force field such as: ...
0
votes
1answer
534 views

MATLAB quad function not work for constant function? [closed]

I want to use the quad function to do the integration today. I wrote a function file: function z=pdf_y1(x) z=100; And then, in the command line, I type: quad('pdf_y1',0,0.5) ...
0
votes
2answers
3k views

Symmetric Matrix Computation (Eigen & C++)

I want to compute a symmetric matrix A from a vector b by: A = b * b'. Does the Eigen library automatically take into account that it does not need to do all calculations to get A (because of the ...
0
votes
1answer
3k views

Convert STL file to other formats like .msh (Gmsh) and .inp (Abaqus)

After reading some stuff on STL files, I realized that they do no contain information about a mesh (connectivity for instance) , but they represent the surface geometry of the part to be meshed. ...
0
votes
1answer
401 views

Fenics : looking forward to compute displacements at nodes

I just went through the Fenics book to get the nodal displacements and tried this code .... ...
0
votes
1answer
9k views

How do I extrapolate data from a NON-LINEAR (logarithmic) standard curve in Excel?

I have made a standard curve. The X-axis is logarithmic. The y-axis is linear. I have added a logarithmic trendline (y = -1.546ln(x) + 39.254; R² = 0.9906). How can I re-arrange the equation to ...
0
votes
1answer
93 views

Unique Partition of a Graph

Given an undirected graph, is it possible to find a criteria that leads to a unique partition of the nodes? The graph is not weighted.
0
votes
1answer
159 views

Neighbor pattern look-up table enumeration on an octree mesh

I am working with an octree mesh where variables are stored in a collocated fashion at octant centers. I want to construct a lookup table for interpolation weights that may occur using only a cell and ...
0
votes
1answer
91 views

mapping data with a spike to a heat map

I have the following dataset that I need to display on the heat map: [30, 15, 66, 7, 9999, 78, 42, 132] So if I map the values to the color scale using a linear function I only see the spike while ...
0
votes
1answer
5k views

Is it possible to access a GPU remotely (i.e., from another machine)? [closed]

I want to access a GPU on a computer remotely, and share this GPU with different desktops. I envision this sort of access as being similar to using a VNC. Is it possible to do something like what I've ...
0
votes
1answer
215 views

Drawing 3d projection of complex surface

I have a complex surface (real dimension 2) in $\mathbb{C}^2$ with coordinates $(z,w)$ given explicitely: for any $\xi \in \mathbb{C}$ I know points $w(\xi)$ of intersection of surface with complex ...
0
votes
1answer
156 views

LP infeasibility

Consider the following original LP: $\mathit{min}$ c'$x$ s.t: $Ax=0 \wedge 0\le x\le 1$ . This is my original LP which has to be solved. Now, using some reductions, I reduced the original LP to the ...
0
votes
1answer
76 views

Method of Lines Runge-Kutta nonlinear stability and behavior

I have a system of 4 nonlinear 1st-order PDEs. I want to solve them numerically by method of lines, first discretizing space. This leads to the system of $N\times 4$ coupled ODEs. $$ \mathbf{u}_{i} =...
0
votes
1answer
48 views

How to use cumtrapz correctly?

I have tried to do a trapeze integration with f(x)=x^2, where I know how the antiderivative looks like, so F(x) = (1/3)x^3 Here's my code, just like I tried: ...
0
votes
1answer
54 views

Differences between openfoam and freefem/fenics

I know a little about fenics and freefem. There exists a big difference between those and OpenFoam? They are used in a similar way (editing a file and writing code)? or perhaps it is made for other ...
0
votes
1answer
54 views

Solving a sparse linear system using transpose of lower triangular matrix without copying

I have a sparse lower-triangular matrix $L$, and a right-hand side $b$, and I'd like to solve the linear system $$L^T x = b$$ but without explicitly creating $L^T$. Ideally, I could write something ...
0
votes
1answer
87 views

Two RK4 method in one program

I want to solve this integral using RK4 by coding in Fortran: $$R=∫1/a(t) dt → dR/dt=1/a(t) =f(t)$$ Initial point: t=0 (or a=0.001) and R=0 And I have to get a(t) by solving another ...
0
votes
1answer
28 views

Norm constraint in CVXPY

I'm trying to implement the algorithm outlined in https://arxiv.org/abs/1211.5608 on a small scale. I have a linear operator $\mathcal{A}$ which is defined as $$\text{trace}(A^*_l(hm^*))$$ where $$A_l ...
0
votes
1answer
44 views

what is non-asymptotic convergence?

I guess convergence in general means it is in asymptotic sense but what does non-asymptotic convergence mean?. Can someone please explain with an example?
0
votes
1answer
26 views

How to check curvature of a vector valued function

In terms of numerical optimization, the newton-rapson method requires a pos. definite Hessian $\nabla^2f$ respectively pos. curvature for computing the next step $p_k$ by solving $$\nabla^2 f p_k = -\...
0
votes
1answer
47 views

problem in interface operator

https://www.unige.ch/~gander/Preprints/42540.pdf. here I have a problem in section $4,$ of approximating the symbol $\sigma_i(k)$. My understanding is, to get back the operator $S_i$ we have to use ...
0
votes
1answer
28 views

Convert existing gmsh mesh from first- to second-order elements?

Is there a way to take an existing gmsh .msh file, and convert it to second-order elements? Specifically, I'm trying to go from 8-point hexahedra (hex8) to 20-point hexahedra (hex20). Ideally, I'd ...
0
votes
1answer
59 views

FDM on nonlinear PDEs

I'm working with a 2D Navier Stokes PDE in the unstabilized version - the equation is a linear equation of the type $\frac{∂u}{∂t} = F(u,t)$. In order to perform time discretization with FDM (finite ...
0
votes
1answer
19 views

Python: Getting second output variable from minimizing a computationally intensive function on first outputs

I have a function in python that is quite computationally expensive to evaluate, of the form: ...
0
votes
1answer
47 views

solve_ivp - Overflow encountered in double_scalars

I'm modeling an electron that orbits the nucleus. Of course, charged particles radiate away there energy so it'll crash into the nucleus. My approach has been to to evaluate the coulomb force and add ...
0
votes
1answer
51 views

Library to solve dense linear system with GMRES

I have a fortran 90 code and I want to solve a dense linear system with GMRES. I would prefer the restarted GMRES with preconditioning. Is there some library that you know of that I could use? Now I ...
0
votes
1answer
48 views

Determining Displacement Field on a Sphere

I need to find the displacement field for this sphere shape in terms of $\delta$. So far, by applying boundary conditions, I know $u_r = u_\theta = u_\phi = 0$ at $r = a$ and $u_r = \delta, u_\theta = ...
0
votes
1answer
125 views

How to visualize the vorticity / flow for a rigid body moving through a fluid?

How can I write down two-dimensional Navier-Stokes equations for a simple rigid object immersed in a flow and freely falling due to gravity? I'm trying to view the vorticity that's induced by the ...
0
votes
1answer
28 views

Avalability of SNOPT optimization solver

I'd like to know if SNOPT solver is available free of cost for academic research in any of the optimization software packages. I came across a few softwares that have SNOPT, but those require a ...

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