# All Questions

5 views

### Free HFSS alternative to create geometry using python

I am using a python script to create wirebond interfaces in Ansys HFSS. Variables define the board, wirebond, and package geometry. To simulate a new wirebond, I just edit the geometry variables and ...
28 views

### Image recognition on Raspberry Pi

I'd like to distinguish different types of beers in my fridge using a Raspberry Pi. I saw a very good tutorial on Adafruit that utilized OpenCV for face recognition. Can these same face recognition ...
65 views

### High frequency noise at solving diffusion equation

I'm trying to simulate a simple diffusion based on Fick's 2nd law. ...
145 views

### Representing Eisenstein numbers without floats

I have a project where I need to use quadratic fields Specifically numbers of the form $a + b \sqrt{-3}$ with $a,b \in \mathbb{Q}$. For example here are the prime numbers in Eisenstein integers: ...
8 views

### plot issue in Comsol Multiphysics

I'm dealing with an Axisymmetric 2D model in Comsol Multiphysics. In other words I working in cylindrical coordinate system. Now I need to build a graphic which represents a changing of some variable ...
14 views

### Mass-conservative reprojection (on a sphere)

I have a 2D distribution of mass on a sphere given as a matrix of masses in latitude-longitude grid cells. I need these masses projected to another grid on the same sphere with different location of ...
52 views

### Large binary programming problem

I have 10000 variables (each of them is binary), vector of positive coefficients and a matrix A (10000*10000), if Aij is 1, then ith and jth variables can take 1 simultaneously, if it's 0, then it's ...
15 views

### Scheme to alleviate (numerical?) instability in system of coupled nonlinear ODEs

I'm solving a system of nonlinear ODEs that take the form $Q_{nm} \ddot{y}_m + S_{nkl}\dot{y}_k\dot{y}_l +V_n = 0$ where Einstein summation is assumed, $y_i$ are the dependent (complex) variables, ...
17 views

### What's the most efficient way to calculate the Wiger quasiprobability distribution?

I want to calculate the Wigner quasiprobability distribution function of a particular wavefunction. The definition suggests a few straightforward ways of calculating it, but I was wondering if there's ...
38 views

For a hobby project I need to solve a series of quadratic programming problems each with about 500 variables about 1000 constraints, each of the form $x_i-x_j\le c_{ij}$ the objective function is ...
100 views

### Publishing a software package along with a paper: licensing

I want to publish the software package I've written for my graduate work along with a paper describing the package. So far I've been considering liberal licenses such as BSD. However, I am now aware ...
10 views

### Any relation between the singular values of each flattening matrices and the core tensor out of Tucker decomposition?

Before I know how to do tucker decomposition, I mistakenly thought the core tensor is only from combining the singular value matrices of the flattening matrices. Yes I know it is not now. For the ...
39 views

### Least squares fitting

I have the following equation I came across which was solved using least squares $x = \sum_{n=1}^{N} A_{n} y_{n}$ Where $x$ is a $m \times p$ matrix and $y$ would be of size $m \times p$ as well ...
35 views

### Optimization of a sum of an absolute vector

$$Mimimize\ \sum\limits_{i=1}^{10} L_{i}x_{i} \\ subject \ to \\ Af=p\ \\ x \geq|f| \\ L, p \ and\ A\ are\ known,\ f\ and\ x\ unknown.\ Af=p\ is\ underdetermined$$ x is minimized when abs(f) is ...
16 views

### Error analysis and the Model Problem

In numerical methods for ODE's, the model problem y' = cy where c is complex is regarded as sufficient in performing error analysis for different methods in ...
9 views

### Optimization with order constraints on parameters

Are there optimizers where it is possible to specify ordinal ranking of parameters? Assume that I have a function of three parameters $f(\theta_1, \theta_2, \theta_3)$. Are there optimizers such that ...
60 views

21 views

### SciDB vs OLAP cube

I am working on good retrieval mechanism for big data systems. I am of view that multidimensional structures could be of great use for aggregations and querying and even i can used them instead of ...
46 views

### Beam finite element stiffness matrix from section constitutive matrix

I'm trying to construct the 12 x 12 beam element stiffness matrix from a section constitutive matrix (6 x 6 with shear stiffnesses, axial stiffness, bending stiffnesses and torsional stiffness on the ...
43 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, ...
35 views

### What is Precision-Recall Curve? [closed]

I have a data mining assignment where I make a content-based image retrieval system. I have 20 images of 5 animals. So in total 100 images. My code returns the 10 most relevant images to an input ...
33 views

### How to measure the computational costs of solving CSPs and optimization problems?

I would like to define an abstract cost (machine and implementation independent measure) of the work needed to solve CSPs as a function of constraint and Jacobian evaluation counts. I am trying to ...
43 views

### Lanczos algorithm with thick restart on a dynamic matrix

According to a recommendation, this is a re-post of that. currently, I'm working on a way to compute the 2 biggest eigenvalues of a real, symmetric, huge and sparse matrix that changes a few entries ...
42 views

### oSVD and cSVD terms

In one article I faced with such terms as sSVD, cSVD and oSVD. As I understand sSVD - standart SVD, cSVD - svd for block-circulant matrices, but I can't find what is oSVD. 1) What is oSVD? 2) Can ...
38 views

### Is there a reference/source paper for the TUCKER_ALS() in Tensor Toolbox for MATLAB?

TUCKER_ALS computes the best rank-(R1,R2,..,Rn) approximation of tensor X, according to the specified dimensions. I am using MATLAB Tensor Toolbox Version 2.5. I am wondering if I write a paper, how ...
39 views

### Computational Science Masters programs [closed]

I have been admitted to a few applied math, computational science, and scientific computing masters programs and am having trouble deciding where to attend. I was admitted to Georgia Tech, UPenn, NYU, ...
79 views

### Dense distributed matrix

A dense matrix is distributed for parallel computation column-wise, then multiplied from left & right by sparse matrices. What would be appropriate c++ libraries for these tasks?
175 views

### Interpolation by Solving a Minimization Problem (Optimization)

I will try to give the motivation behind this problem and later the math formality. Given a grayscale image (1 Channel - M by N Matrix). Someone marks some pixels as anchors. Now, you need to ...
67 views

### How to solve singular non symmetric poisson equation with Neumann boundary condtions?

I am trying to solve 2D Poisson equations with Neumann boundary conditions. When the mesh is uniform, Poisson equation is singular and symmetric, so the method listed in Null Space Projection for ...
77 views

### finite volume for diffusion equation with anisotropic (tensor) coefficient

Consider the scalar PDE for $u$ with Dirichlet boundary conditions: $\mathrm{div}(\mathcal{K}\nabla u) = f\; \forall x\; \in \Omega \subset R^2$, $u = 0 \; \forall \; x\;\in \partial\Omega$ ...
34 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 ...