Computing Definition and 683 Threads

So I ran an ODE solver with an additional, random (using randn) injected input. Then I took the same ODE solver and the same random line, and multiplied it by 5, so now I have (5*randn). The runtime is already ten times as long (and still not finished). Why does it take so much longer to...

I'm in my first year of theoretical physics master and I'm considering of following the path of scientific simulations. At the moment I use C for my simulations. I would additionally like to learn an object oriented language. I followed a course in Java about 2 years ago, so that would be easier...

hi , I need to create a program on mathématica 8 to study the stability of my system using Floquet transition matrix . to compute the Floquet transition matrix I made this program based on a fourth order Runge Kutta integration : X1[t_] = {x1[t], x2[t], x3[t], x4[t], x5[t], x6[t] ...

Hi, I have a catalog of dark matter halos, which consists of their COM positions and their masses. I need to determine the halo mass function. How can I do? I mean, it is easy to plot the number of halos between mass M and M+dM, but how can I have information on the volume? I don't get it...

Good day. just want to ask anyone about copper loss. How is it computed for example in a manufacturing plant or in a dept mall.Could anyone give an illustration/example? Also , is it true that copper loss can be reduced by using big wires?What if the wire is big enough? thank you. hope...

Hey Everyone! I'm looking for a good tool to do some high performance computing and analysis for my research. I've been going back and forth about using Excel as my primary tool as it is pretty straight forward so that I can share my data and results with others. Does anyone have any thought...

More recent book than Nielsen and Chuang "Quantum Computation and Quantum Informaion" For this famous book, I discovered too late that there are no References more recent than 2000. Do you know of a textbook that covers more recent developments in Quantum Computing? Thanks Don Parsons

question A ciclindrical metal specimen 10 mm in diameter is stressed elastically in tension. A force of 15000 N produces a reduction in diameter of 0.007 mm. Compute Poisson ratio if its elastic modulus is 100 GPa my attempt D original = 0.01m change in D = 0.000007m F=15000N E=...

I'm writing a program that generates every possible valid Mastermind code. That itself is easy. There are 6 colors in 4 possible positions. Cycling through them all is done like so: for(int i = 0 to 1295 ) { // 1295 == 6^4 - 1, there are 1296 possible permutations of colors color1 = (...

Homework Statement The random variable X has the probability density f(x) defined by: f(x) = ke(-|x|) Compute the constant k, then find the probability density of Y=X2 Homework Equations The Attempt at a Solution I'm completely stumped by this question. I know I need to...

I'll be concentrating in/researching aerodynamics and CFD. Will I be doing the programming/mesh generation/code execution (or any other intensive computing) on my own computer or the department's super computer/workstations? I had a powerful desktop in ME undergrad and frankly it wasn't really...

We are given a vector field: F=\frac{-y}{x^2+y^2} , \frac{x}{x^2+y^2} Then asked if F is conservative on R2 \ (0,0). I just solved the partial derivatives of each part of the vector field and they did indeed equal each other, but I don't under stand what the "\(0,0)" part means. We are then...

Any thoughts on what home computing will be like in 50 years? How about 100 years. Real time Google Earth for sure. Much more mind to computer interface. We might put something like a headset on that would read brain info. Artificial intelligence? Here's a quote from another post here-...

http://www.quora.com/How-do-I-become-a-data-scientist Huge collections of resources can be found at http://www.quora.com/Alex-Kamil/answers (you can edit them too) For example, http://www.quora.com/What-are-some-good-resources-for-learning-about-distributed-computing...

Really stuck... computing orthogonal complement? Homework Statement The Attempt at a Solution :cry: I'm really sorry I can't provide much here because I really don't know how to proceed. Could anyone offer a hint to get me started?

General computing ? On my computer the internet connection has been down for 3 months and now its been fixed I can't sign into MSN and I can't set a desk top back ground either. Does anyone know how I can sort these problems out??

Homework Statement If A, B are elements of Mat(n, R) and A is invertible, compute \frac{d}{dt}_{t=0}(A+tB)^{-1} The Attempt at a Solution The derivative will be of the form \frac{d}{dt}(A+tB)^{-1}=-(A+tB)^{-1}\frac{d}{dt}((A+tB))(A+tB)^{-1} but I need to evaluate this at t=0...

Hello, Homework Statement My problem regards the disk|washer, and cylindrical shell methods for finding volumes in single variable calc. My problem is basically am I understanding these two methods and their relationships properly. Fundamentally, these methods are indentical, as we can...

Homework Statement I am given this parametrization of the mobius band: F(s,t) = (cos(t)+s*cos(t)*cos(t/2), sin(t)+s*sin(t)*cos(t/2), s*sin(t/2)) Let F1 be F restricted to (0,2*pi) X (-1,1). Let F2 be F restricted to (-pi,pi) X (-1,1). let N1 be the unit normal field determined by F1 let...

When will quantum computers become useful? For example, cracking some real-world encryption, simulating quantum behaviour of molecules, or enhancing web search engines? I somehow have the impression that this is a field of physics where theorists keep dreaming and experimentalists keep playing...

A friend of mine told me he fielded this at an oral exam: "Compute the classical action S for a particle of mass m in a gravitational field U = -\alpha/r." I know the formula for the classical action is given by S = \int_{t_i}^{t_f} L(q,\dot q,t) dt, and that for a particle in a...

Hi, I wanted to know if someone who has a degree in parallel computing and related work experience will be able to get a PhD project in Computational Astrophysics? What other skill sets would the person require? I have seen many PhD positions that accept people from a parallel computing...

Hi, I'm a second year physics major with specialization in computational physics, and I have recently become interested in quantum computing, and stuff dealing with computers like the memory cell nanoribbons made of graphene. I wanted know if I am currently pursing the best degree to get...

Homework Statement See figure attached, Homework Equations The Attempt at a Solution Isn't the Maclaurin series just simply the Taylor series around 0? (\text{i.e. } (x-c), \quad c=0, \quad x ) Also for part B, how do we go about solving for | \epsilon_{t} |? Thanks...

Hi everyone, I need help with this problem. I just can't get it: Let a,b,c,d,e and f be vectors such that \langle a,b \rangle=-4, \quad \langle a,c \rangle=-9, \quad \langle b,c \rangle=2, \quad b+c=d, \quad -4 a+3 b=e and -4 b+5 c=f. Compute the following inner products: \langle b,a...

• P1 takes n days to run • P2 takes n^2 days to run • P3 takes 2^n days to run • P4 takes log(n) in base 2 days to run So, to run P2 on an n of 4 would take 16 days. a. For each version of the program, calculate the value of n (rounded down) we could compute if we let the program run for...

I need to calculate \left[ H , \ \frac{1}{r} \mathbf{r} \right] . My initial idea is to use \left[ H, \ U \mathbf{r} \right] = \left[ H, \ U \right] \mathbf{r} + U \left[ H , \ \mathbf{r} \right] . Then clearly \left[H , \ U \right] \psi = \frac{ - \hbar ^{2} }{2m} \left( \nabla ^{2}...

Hi all, I have a question about trapped ion. How can they achieve such stable frequencies if the power supply which supply's the ion trap drifts over time? For example if you use a paul trap as an atomic clock, how do you compensate for any fluctuations in power supply voltage and frequency?

So I've read through beginning alg topology really fast and there are a lot of theorems and methods for computing fundamental groups but what are the most useful tools? When asked to compute the fundamental group what should one do? try to find a deformation retract and compute the fund group...

http://www.physorg.com/news/2010-12-ibm-breakthrough-chip-technology-path.html Can Microsoft or AMD use this Nanophotonics chip technology? Can they say goodbye to Moore's Law after this breakthrough?

Homework Statement Show that G(q_2,q_1;t)=\mathcal{N}\frac{e^{iS_{lc}}}{\sqrt{\det A}} where \mathcal{N} is a normalization factor independent of q1, q2, t, and w. Using the known case of w=0, write a formula for G such that there is no unknown normalization factor. Homework Equations I...

Let T: R[x]2\rightarrow R[x]3 be defined by T(P(x))=xP(x). Compute the matrix of x with respect to bases {1,x,x2} and {1,x,x2,x3}. Find the kernel and image of T. I know how to do this when given bases without exponents, however I do not know exactly what this is saying and therefore am...

I'm a third year physics student and just wanted to know for the future, what books should I get in order to learn more about Quantum Computing (theory behind it)? I know Quantum Mechanics books, yes, but what else like after graduation? Thanks so much! So far on my list is just books on...

Let X have density function fx(x)=1/x^2 for x>1, otherwise fx(x)=0. Let Y=X^(1/3). Compute the density function fy(y) for Y. my attempt ------------ P(X<=1)=0 P(Y^3<=1)=P(Y<=1)=0 P(1<x<inf)=P(1<Y^3<inf) =1-P(Y<1) i am stuck here. The answer to this is fy(y) = 3y^4 for y>1 and...

Asked myself that question today, and I don't know what the answer is. Maybe I missed something somewhere in the math... Anyone know?

Hi, I have the following problem: Suppose you have a coin that has chance p of landing heads. Suppose you flip the coin n times and let X denote the number of 'head runs' in n flips. A 'head run' is defined as any sequence of heads. For example the sequence HHTHHHHHTTTTHHTHT contains 4 head...

I have some questions about the very new and theoretical field of quantum computing and would love to learn more. Is, or are there any good informational places where I can learn more? I have already looked at the wikipedia page but it simply left me in wanting.

We use the antisymmetric Fock space ( "fermions"). We denote by c(h) a creator operator. I need to evaluate the following quantity: < \Omega , \big(c(h_1)+c(h_1)^{*}\big)\big(c(h_2)+c(h_2)^{*}\big) \ldots \big(c(h_n)+c(h_n)^*\big)\Omega> where \Omega is the unit vector called vaccum...

Homework Statement The notation [x] denotes the greatest integer <= x "integral sign" with a lower limit of -1 and a upper limit of 3 [x] dx Homework Equations I would like to know how to enter symbols for certain problems. I am lost when Apostol says "the notation [x] denotes the...

Hello physicists! I'm a comp sci student and I am trying to graphically model a simplified version of the solar system as part of a programming exercise. In order to apply the gravitational forces to the planets, I need to compute the Jacobian matrix as it relates to two particles (planetary...

I have small question computing vacuum expectation values here http://www.cns.gatech.edu/FieldTheory/extras/SrednickiQFT03.pdf" from Mark Srednicki. My problem is with equation 210 on the pdf page 69. In the second line of 210, where does the second term come from? Z(J) and W(J) are defined...

Find the characteristic polynomial, eigenvectors, and eigenvalues of the matrix. [ 2 -2 3 0 3 -2 0 -1 2 ] My characteristic poly is x^3 - 7x^2 + 14x - 8 The roots are 1, 2, and 4. When solving the system, (2I - A)x = 0 I get: [ 0 1 0 0 0 0 1 0 0 0 0 0 ] Can...

Hello people of physics I am writing a paper for an undergraduate quantum mechanics course (my second quantum course) on the following topic The role of entanglement in quantum computing Just wondering if somebody could recommend a good paper or a good book on this topic. Any suggestions...

How do we define veliocity of a particle in QM? How it's related to the momentum. Are there any ways to cimpute quickly mean value of veliocity.

http://www.nag.co.uk/sc22wg5/ It looks like Fortran 2008 is going through its final steps of standardization. What does this mean for scientific computing? Since people still use Fortran 90 despite new revisions up to 2003, will this go under the radar, or will this be a new and useful...

Homework Statement \int^{1}_{0}\frac{dx}{\sqrt{1-x^{2}}} Homework Equations None The Attempt at a Solution \int^{1}_{0}\frac{dx}{\sqrt{1-x^{2}}} = sin^{-1}x\right|^{1}_{0} sin^{-1}x\right|^{1}_{0} = \frac{\pi}{2} - 0 so the final answer is just pi/2. I have no problem computing the...

Hi All - My name is Dan Sandberg and I am studying physical chemistry at the Univ. of Connecticut in the USA. I recently heard a talk on quantum computing and, at the time, began to picture a quantum computer which employed a photoactive protein. I decided to attempt to see this idea to...

I am trying to find the deflection of the beam as described below, The beam has an overall length L and a load Q acting downwards at this point, the question is asking for the deflection of the beam at the point three quarters of the way along the beam. The beam has constant flexural rigidity...

Homework Statement This is problem 2(a) from my midterm review sheet, found here: http://www.math.washington.edu/~sullivan/326smt_sp10.pdf Homework Equations Not sure what exactly I need here The Attempt at a Solution By the quotient rule, ∂f/∂x =...

I want to compute x within 0.1% relative error with Simpson method, these are my m-files. Which command i should add for this? function simps(a, b, n) %simps(a, b, n) approximates the integral of a function f(x) in the %interval [a;b] by the composite simpson rule %n is the number of...