# Questions tagged [terminology]

For questions about words, phrases and definitions that are specific to computational science.

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### When is a dynamical system periodic?

Say a system of ODEs describing a dynamical system, with solutions/state-space vectors ($x$, $y$, $\theta$). If values of $y$ and $\theta$ repeat but values of $x$ do not, would I say that the ...
72 views

### Is the sine function periodic in $x$ or $y$?

I know sine is $2\pi$-periodic, but some people say the motion is "periodic in..." Would it be periodic in $y$? If we move along the $x$-axis, the function values $y = \sin(x)$ will repeat, ...
77 views

### Is the Immersed Boundary (IB) method a Direct Numerical Simulation?

Is the Immersed Boundary (IB) method considered a Direct Numerical Simulation? A DNS code is the most detailed type of simulation and the most accurate but computationally expensive, right? What makes ...
38 views

### Origin of phrase `computational microscope'

I have heard the term 'computational microscope' used to describe the practice of molecular simulation (in the context e.g. computational chemistry, materials science) and its use as a numerical tool ...
81 views

### How to pronounce Eulerian when giving a talk? [closed]

When one gives a computational methods talk, what's the right way to pronounce "Eulerian"? Is it like oiler-ree-in, 5 syllables, or oh-lure-ree-in, 4 syllables? Langrangian is simple: Langrange-...
49 views

### Is “sensitivity” a term in numerical computation?

The section 4.2 "Poor Conditioning" in the book Deep Learning defines the condition number of the function $f(x) = A^{-1}x$ as \begin{align} \underset{i,j}{\max}~ \Bigg| \frac{\lambda_i}{ \...
88 views

### Difference between phenomenological modeling and mathematical modeling

Is there a difference between phenomenological modeling and mathematical modeling? When reading a few journal papers, I often see the former being used -- is it just fancier wording? If it's relevant,...
157 views

### What is the difference between Methods of Weighted Residuals and Spectral Methods?

Methods of Weighted Residuals (MWR)  usually include Galerkin, collocation, method of moments, least-squares and subdomain methods. Spectral methods  usually include Galerkin, tau and ...
153 views

### What is eighth order central difference?

The origin of the question can be found here. I know the details about forward, backward and central differences. If $u$ is the variable, does eight order means it approximates the $u_{xx}$ using $u$...
125 views

### Why don't we call the simulation “a model for …”?

When a set of model equations, e.g. some coupled differential equations, has solutions that behave in ways similar to real-life phenomena such as blood flow in the heart, a wave movement, or a plate ...
50 views

### Term for an small optimisation algorithm used as a subroutine

Is there a term describing a specialised solver which is used as a subroutine or a different, larger solver? For example, a gradient descent solver which, at each step, uses a line search to optimise ...
51 views

### Is it Grid/Cluster/Cloud Computing? How are those terms defined?

There are three very connected and widely used terms: Grid and grid computing Cluster and cluster computing Cloud and cloud computing In many situations, it is not obvious which term to use, as I ...
122 views

### Is saying “math modeling and numerical simulation” wordy and redundant?

I'm describing some work on my website, and I'm wondering if my math modeling and computer simulation work is described ok: I say math modeling and numerical simulation. Should I say "...
70 views

### What is ABA and BAB schemes when talking about numerical integrators

I have read a lot about numerical integrators (ode solvers) lately and tried reading a few papers but I have stumbled upon something that I can't understand and it's something called ABA and BAB. ...
76 views

### What is the name for this type of constraint?

I have what would be a straightforward mixed-integer linear programming problem, except for the fact that some of the constraints are of the form $f(x_1,x_2,x_3,\ldots,x_n) < c$, where $f$ is 'take ...
91 views

### What are the names of the variables in the linear system $Ax=b$

I've been discretizing PDEs and formulating $Ax=b$ systems, and yet I don't really know what the $A$ and $b$ are in words. I occasionally call the $A$ matrix the "Jacobian matrix," but for linear ...
491 views

### What is the difference between recursive bisection and direct k-way partition?

The usual problem of graph partitioning is to split a graph (or a mesh) into two partitions. According to its Github repository's README file, KaHyPar supports both recursive bisection and direct k-...
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### Is there a term for Goodhart's Law in the context of optimization?

Let's say I'm optimizing something. To pick an arbitrary example, let's say I'm choosing the shape of some part to maximize strength-to-weight ratio. So I get some FEM software, parametrize the shape, ...
2k views

### Does this “reverse binary search” have a name?

Normally when searching in sorted sets, binary searches are a fast, nice and easy way to locate data. It does however break down in the hypothetical scenario of having a set of arbitrarily large but ...
448 views

### applications of computational geometry in fields such as CFD?

Out of curiosity, I was recently trying to search what skills are required to be successful as developer in scientific computing field (e.g. CFD or similar). And to do so, I was going to through ...