Computation Definition and 231 Threads

Hi, all. I have a function in Matlab. I'd like to calculate the computation time of the function. How can I obtain the time? I think Matlab must include related functions as its internal functions. Thanks in advance.

Hello, I'm a 4th year physics undergrad, so I'm about to decide what to do in my undergrad thesis. I'll do pure theoretical work, but I'd like to avoid copy-paste stuff and come up wityh something quite original, however I'm not sure what topic are available, maybe someone here will help...

I need to compute the integral: \int_{0}^{\infty}dx\frac{cos(x)}{cosh(x)} so obviously i need to use the residue theorem here and evaluate the contour integral of the complex function (cos(z)/cosh(z)) the singularity point here is z=i\pi/2 the intervals i decided to do the are...

Compute the line integral \int_{C} F\cdot dr where F = -y i + x j. The directed path C in the xy-plane consists of two parts: i) a left semicircle from (0, -1) to (0, 1) with center at the origin, and ii) a straight line segment from (0,1) to (2,1). i) r(t) = cos t i + sin t j [pi/2 <=t<=...

Dear every memeber, I encountered the numerical computation on the following differential equations. I use four-step Runge-Kutta methods to integrate, but the result is not converge, even if I take the time step (t=0.0001). please help me why so? Could you please tellme which Fortran...

I've written a program that repeats a calculation a certain number of times in single precision, then in double precision. The times are recorded by the cpu_time(real t1) subroutine. (Specifically, the calculation is aReal/(aReal+0.01) .) It seems that the time for the double calculation is 1.20...

There is a computer forum and a brain forum. I don't know which to choose. But I'll go here. Computers made more progress in the last ten years than cars did in the last hundred. But Blue Gene still falls short of the speed attributed to three pounds of goo in my head (20 quadrillion ops per...

For example, in tight binding model, the site energy is random I want to have 100 disorder realizations, then I have the following two questions: 1. Do different realization needs different seed in the random number generation subroutine? 2. When all realizations are completed, the...

"straightforward computation..." Hello. I am reading a paper that discusses moving from a regular NxN dimensional Hilbert space into and N^2 X N^2 dimensional Liouville space. The density matrix can be re-written as a 1 X N^2 vector by stacking the rows and the Liouvile equation can be...

I'm wondering if there are any convenient symbolic "shortcuts" (i.e. abuse of notation) that enable one to compute the gradient with respect to a certain vector, without decomposing the computation into the vector's individual elements and differentiating with respect to each element. For...

i need to solve/prove the next two integrals: \int\frac{dx}{u^2+u+4} and i need to show that: \int_{0}^{\pi}\sqrt{1+sinx}dx=4 the problem is that i have a clue to substitute u=sinx and then sin(pi)=0=sin0 so the integral should be equal zero, is it not? ofcourse the integrand becomes...

The following tech talk at google discusses using humans to collect useful information for things such as images, using games. It's an interesting approach, which certainly makes a lot of sense. http://video.google.com/videoplay?docid=-8246463980976635143&q=techtalk&hl=en

I thought this might be a well-used thread if I asked the following: What computer skills do physicists use in their work? Please tell me what technology you have learned for whatever job you do. This questions mostly geared toward those of you guys out in the field, not fellow undergrads...

I am taking this course this semester and i don't have enough idea about what this is all about...like i want to have a clearcut view in mind like how this coyrse helps...please i appreciate your comments.. Syllabus runs as:: Theory of Computation Course Contents: Models of computation...

Nice lectures describing the theory of Quantum Computation. I'm currently watching them. http://www.quiprocone.org/Protected/DD_lectures.htm

Hey all, I'm a beginner of the Quantum Computation and Quantum Information. For a long time, I feel very confuse about the question bellow. Could you do me a favor and show me the proof? Many thanks! Question: Show that any qubit can be expressed as psi=exp(iγ)[cos(θ/2)0+exp(iΦ)sin(θ/2)1]...

I'm doing a research paper on the deutsch problem in QC. My google inquiries have turned up numerous papers on solutions to the problem, but I am having difficulty finding a clear formulation of the problem itself. Can someone point me in the direction of this information?

I hope this news isn't moved to another forum - many of our readers would be interested in this: Quantum computer solves problem, without running http://www.news.uiuc.edu/news/06/0222quantum.html "It seems absolutely bizarre that counterfactual computation – using information that is...

So, as I have found out through my exhaustive search for a solid grad program, it is hard to find a close-knit group of quantum-computation-ers. After tossing a coin 3 times, I found the best place to look for anyone interested in the field is in this group rather than Computers or Engineering...

i need to compute the lim of (1+2/x)^x or (1-1/x)^x and (1+1/x)^(x+3) when x approaches infinity. if you can provide a steady method to compute it, it will be appreciated. btw i know that lim (1+1/x)^x as x->inf is "e", but does it have any correlation to here.

I am trying to write a very simple program in Liberty Basic. The last step in the program gives me a answer in inches, and I want to convert it to feet. So I figured I would simply divide the answer in inches by 12, then multiply ONLY the decimal value by 12, and then I would have the value in...

Is logic & computation two sides of the same coin.?if yes,How?

Are there any computer programs, or computer systems out there that can compute trigonometric values for cosine for large numbers like cos((pi)*t) = cos((pi)*2.34579^2000) to an accuracy of three decimal spaces? Where pi is the number 3.1415...n If so, what systems are available, how might...

Hi, I need help for this problem: Find the eignevalues and eingenvectors for the matrix below. DO NOT compute them directly by computing the matrix: A-1 We need to find some kind of demonstration to see if the eignevalues of A-1 are the same, opposite or inverse (or whatever) as those of...

Hi , I have difficulty to find the folowing questions about limit computation. IF lim xy/(x^2+y^2) ( when (x,y)---(0,0)) Evaluate the limit as (x,y) approaches the origin along: a) The spiral r=0, θ >0 b) The differentiable curve y=f(x), with f(0)=0 c) The arc r=sin(θ ) Thank you B

This regards an article found in the journal of Nature, 26 Aug. '04. I thought it might be interesting, not so much for the physics it presents (although they are certainly fascinating) but because of the implications. I think a discussion around the questions provided at the end of this essay...

course called "scientific and engineering computation" I am taking a course called "scientific and engineering computation" using the MATLAB program and I was just wondering where should I post questions on this topic?

How to find a short-term Visiting Position in the area of Quantum Computation? I interesting to collaboration with other research groups. One of my results is Probabilistic Simulation of entangled states and Quantum Computation. I have the computer's program for simulation of Qubits in Pascal...

Ten years ago (Science 1994;266:1021-4), Adelman built the first DNA based computer to solve the so-called Hamilton Path problem for seven nodes. SAT problems were solved with similar approaches by Lipton (Science 1995;268:542-5), with a DNA-based algorithm and Faulhammer (PNAS 2000;97.1385-9)...

can someone explain algorithmic cooling to me? (i think that's what it's called.) in a work of fiction i am presently reading, an interior space is cooled by a quantum-computational device engaged in ongoing calculations. the book is 'redemption ark' by alastair reynolds and the technology is...

Quantum mechanics allows one to compute in a way fundamentally different from any way to compute classically, at least in theory. Will quantum field theory allow new kinds of computing that go beyond quantum computing? I would have suspected not, but for example this paper argues that it may...