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Solving SDEs in R until a prespecified value is reached

I am trying to solve a system of SDEs in R using the Diffeqr package. A simplified version of the system: ...
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Normalising DFTs Correctly

I have been playing around with convolutions in scipy's signal package: ...
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Efficient Alternatives to Operator Splitting in NLSE

Lately i've been trying to decide my thesis theme and i've become interested in adaptive finite elements and finite volumes algorithms. However, I need my thesis to fit into a physics related theme. ...
97 views

How to perform an eigendecomposition of a general complex matrix with arbitrary precision in C/C++

I need to obtain the Eigenvectors of a general complex matrix, but with quadruple precision. Is anyone aware of a means to do this? I currently use Tux Eigen, and I see that in their unsupported ...
13 views

How to handle system of chemical reactions for a batch reactor SciPy solver

I have a system of chemical reactions where the rate equations represent a batch reactor model. The model is a system of ODEs which is solved with the SciPy ...
58 views

Probability approximation: monte carlo VS sde

I have a probability measure $\mu$ (say, in $\mathbb{R}^{d}$, with density) and I want to approximate it numerically. Today I noticed that my measure is ergotic for a certain Stochastic Differential ...
37 views

What is the format of saving sparse matrix in MATLAB?

We know that for lagre sparse matrices, we can use compressed sparse row (CSR) or compressed sparse column (CSC) format to store the sparse matrices so that we can save CPU memory. And the coordinate ...
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Implementing Housholder QR decomposition in Python

I am struggling to get my implementation of householder qr decompostion to generate the correct answers. I have been working on this for days and cannot workout where my code is going wrong. Any help ...
38 views

Hybrid Ellpack-Itpack (ELL) + COO Sparse Matrix Representation decomposition threshold

Hybrid ELL-COO sparse matrix representation can be done as in the picture, I was looking intensively, however I couldn't find out what is the threshold of decomposing the original matrix into ELL part ...
20 views

Interpreting results of using no-flux boundary condition

I am solving for solute transport in 1 D. $$\frac{\partial C}{\partial t} = D\frac{\partial ^2 C}{\partial x^2} - v\frac{\partial C}{\partial x}$$ No-flux boundary condition is imposed at both the ...
82 views

How to use matlab command 'fft' to solve Ax=b arising from Poisson equation?

I want to ask a question about fast solver to the Poisson equation with Homogenous boundary conditions as follows: $$-\Delta u = f.$$ After centered difference using $n+2$ equidistance points in all ...
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Live audio processing using c++ (standard or external libs 'ue4')

My goal is to get audio from the input of another device (either connected to computer throught aux or audio interface threw rca or coaxil(from an external device playing audio live) adapters to line ...
35 views

Low rank update of QR of inverse

I am in a situation where as part of a sort of inverse power method scheme, I want to very often perform the following step: Apply a symmetric rank one update $uu^\top$ to my inverse matrix $A^{-1}$ ...
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Smoothed Particle Hydrodynamics: Weird clustering of particles. Is that normal?

I implemented a rather simple SPH simulation using a cubic-spline-kernel and a simple non-iterative pressure solver as described in this PDF in equation 9. I followed algorithm 1 of that paper (...
28 views

Why the iteration steps become twice if the step size reduces half for CG methods?

For CG method for SPD matrices, (Ax = b arising from Poisson equation with homogeneous boundary condition) we know that the convergence theorem: After m steps of iteration, the error $e^{(m)}=x-x_m$ ...
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Counting number of calls to union operation while creating disjoint set from an undirected graph

I am working through an algorithms book, and I am having trouble understanding the solution to a problem in the book. This is found in the Introductions to Algorithms book in Chapter 21 on disjoint ...
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Run different architecture on a PC with coprocessors [closed]

Before I start, I'm sorry if this is offtopic here, but I couldn't find a more suitable site where to post this question. Inrecently saw a video of an old machintosh computer running msdos software, ...
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I have a trouble determining appropriate transition matrix

M.Sc students of the Department of statistics, FUTA are expected to do course work for a year and write their thesis the following year before graduating. A student has a probability of 0.25 of ...
43 views

Is there an open-source material database management GUI?

Does somebody know an open-source GUI for the management of a small material database? I have a spreadsheet with some materials in it. Each materials has some temperature-dependent properties like ...
Analytic formula for leading eigenvector of $uu^T + vv^T$?
Let $u$ and $v$ be nonzero column vectors of size $n$ and consider the $n \times n$ positive-definite matrix $A:=uu^T + vv^T$. In this post https://math.stackexchange.com/a/112201/168758, the ...