What is Computation: Definition and 248 Discussions

Computation is any type of calculation that includes both arithmetical and non-arithmetical steps and which follows a well-defined model (e.g. an algorithm).
Mechanical or electronic devices (or, historically, people) that perform computations are known as computers. An especially well-known discipline of the study of computation is computer science.

View More On Wikipedia.org
Recent contents Top users
  1. M

    Magnetic Field Computation from Thick Rectangular Conductor

    Hello, and thanks in advance for taking a look at my question. Generally, I am trying to make a railgun force model. Since railguns depend on the magnetic field created around the rails (and the resulting Lorentz force) I need to model the magnetic field created by the current that flows...
  2. S

    I Where to find full core-to-surface profiles of stars?

    I need to run some computations using an initial star. I could evolve one using MESA but it'd be very convenient if I could download a ready made profile/model of a star which details things like mass, dens, temp, etc, from core to surface. I've googled for a long time but I just keep getting...
  3. Experience111

    A 4th order tensor inverse and double dot product computation

    Hi everyone, I am currently working on a subject that involves a lot of 4th order tensors computations including double dot product and inverse of fourth order tensors. First the definitions so that we are on the same page. What I call the double dot product is : $$ (A:B)_{ijkl} =...
  4. hilbert2

    Comparison of high-level computer programming languages

    A little question about the appropriateness of a certain research subject... Would it be useful to make a study of the computational effectiveness of equivalent codes written with Matlab, Mathematica, R Code, Julia, Python, etc. in a set of typical computational engineering problems like...
  5. J

    MATLAB Octave integral computation help

    Hello, I'm having some trouble with my octave coding and would appreciate any input on where the issue lies. The coding is as follows: age = [0:1:100]; %this is the age matrix, represented by a time = [0:1:100]; %this is the time matrix...
  6. binbagsss

    Elliptic functions, residue computation, same zeros and poles

    Homework Statement Hi, I am trying to understand the attached: I know that if two functions have zeros and poles at the same point and of the same order then they differ only by a multiplicative constant, so that is fine, as both have a double zero at ##z=w_j/2## and a double pole at...
  7. peroAlex

    Engineering RL Circuit Power Computation: What Am I Missing in My Solution?

    I'm having some problems understanding why my computation deviates from solutions. I thank in advance to anyone who can give me some tips where I've gone wrong. Homework Statement Compute real power on resistors ## R_1 ## and ## R_2 ## and reactive power on inductor ## L ##. Circuit is powered...
  8. Luca_Mantani

    A Computation of anomalous dimension in MS scheme

    Hi, I am computing the anomalous dimension of a mass operator in the MSbar scheme, but i have a doubt. The following is the solution of an exercise given by a professor but i don't understand a passage. I have computed the counterterm ##\delta## and i have the formula $$\gamma=-\mu...
  9. N

    MHB Calculate Strings with int calculate(string exp) Function

    If input is 2: call int calculate(string exp) function. This function will return the computation of a string expression (exp). For example: calculate(“54321+222”) will return 54543 calculate(“120*20”) will return 2400 calculate(“235/3”) will return 78 calculate(“356-32”) will return 324My code...
  10. C

    I Superfluidic Quantum Computer?

    Would it be possible to make a quantum computer with fluidic logic (https://en.m.wikipedia.org/wiki/Fluidics), using a superfluid, like liquid Helium-4, as the the "current"?
  11. Ventrella

    A Physics and Integer Computation with Eisenstein Integers

    I realize this question may not have an obvious answer, but I am curious: I am using Gaussian and Eisenstein integer domains for geometry research. The Gaussian integers can be described using pairs of rational integers (referring to the real and imaginary dimensions of the complex plane). And...
  12. Apollo16

    Research Area for Nuclear Engineering Ph.D

    So I'm currently a senior undergraduate nuclear engineer at a respected university and I've been considering getting my Ph.D for a while now. I'm having difficulty deciding on a specific research area, however. I'd like my research, optimally, to be applicable outside the nuclear sector as well...
  13. evinda

    MHB What are some alternative topics for a Theory of Computation presentation?

    Hello! (Wave) Could you suggest me other topics for a presentation in Theory of Computation other than the ones that were suggested by Evgeny Makarov to mathmari in this post: http://mathhelpboards.com/chat-room-9/computability-14368.html#post67959 ? Is for example the topic Algorithmic...
  14. Tone L

    Significant digit computation time

    If I am performing simple arithmetic on numbers that extend 12 decimal places i.g; 12.1234567891011 +11.1234567891011 and this calculation occurs 1000+ times, will calculation i.g; 12.123+11.123 speed up computation time if so how much and how do you arrive at this?
  15. L

    If there's any website that can upload my programming script

    Hi there, Apologize in advance if this is not the correct place to post my query. I've been googling didn't get it or maybe my input search parameter is not sufficient or irrelevant. I am recently doing my graduate in physics and my inclination towards computational physics makes me to do my...
  16. hernando Jose

    Introducing Isogeometric Analysis: A Beginner's Guide for Mechanical Engineers

    I'm a mechanical engineering from Universidad Tecnologica de Bolivar(Cartagena Colombia) . Right know studying Computational mechanic material(more specific: Isogeometric analysis). I'm really newbie in this and hope than some on your can help me because is just the beginning of something more...
  17. A

    Help with nanoparticle and computation

    I have access to a nanoparticle that no one has done a computational study on. I want to know specifically what kind of computational studies i can do on it. e.g Ab initio calculations and m.d. simulations. I want to know what properties could be computed and how to go about it.
  18. Nantes

    Thermodynamic cost of information processing (or lack thereof)

    Say you wanted to heat up your room. You could choose between an electric heater that outputs 500W or a PC that draws 500W. In both cases, the amount your room would heat up by would be the same, but the second case is much more advantageous because the computer can process information before...
  19. evinda

    MHB NFA Hello! (Wave) - Computation Theory Explanation

    Hello! (Wave) According to the book of Michael Sipser: Introduction to the Theory of Computation we have the following: Could you explain to me why after having read the first 0, we can go to state $q_3$ ? I have drawn the tree and I find also an other result after having read the...
  20. L

    Computations Using Playing Cards

    EXPLORING THE POSSIBILITY OF PERFORMING COMPUTATIONS WITH PLAYING CARDS I was listening to an interview with John Conway yesterday and the conversation turned to his "Game of Life". Conway mentioned that Life can be configured in such a way that it can perform arbitrary computations. This got...
  21. Mr Davis 97

    B How can I perform decimal computation by hand?

    I have to perform the following computation by hand to get a number within two decimal places: ##\displaystyle (120)(\frac{54.30}{194.79})##. The answer is 33.45, but how can I do this by hand?
  22. hilbert2

    Programming an XBox One to do scientific computation?

    Hi, I've done quite a bit of scientific computation at work, mainly related to molecular QM and dynamics of hyperelastic bodies... I've used C++ to write the code for those applications. I also do some other simulations at home in my free time, just for fun. My home laptop isn't exactly the...
  23. S

    I Some questions about eigenvector computation

    NOTE: For the answers to all these questions, I'd like an explanation (or a reference to a book or internet page) of how the answer has been derived. This question can be presumed to be for the general eigenproblem in which [ K ] & [ M ] are Hermitian matrices, with [ M ] also being positive...
  24. Ben Wilson

    Efficient 3D Inverse Fourier Transform on FORTRAN Code with Chi Array

    Hi, I have a FORTRAN code with an array called Chi that I want to run an inverse FT on. I have defined two spaces X and K which each consist of 3 vectors running across my physical verse and inverse space. My code (If it works??) is extremely slow and inefficient (see below). What is the best...
  25. J

    A Quantum versus classical computation of the density of state

    Hi, If I consider for instance N non interacting particles in a box, I can compute the energy spectrum quantum mechanically, and thus the number of (quantum) microstates corresponding to a total energy between $E_0$ and $E_0 + \delta E$. In the limit of large quantum numbers, the result is well...
  26. JotWe

    I Combined measurement uncertainty for mass computation

    Problem I would like to determine the combined standard measurement uncertainty for a mean mass ##\bar{m}## computed from a mean volume ##\bar{V}## and a constant density ##\rho## with $$\bar{m} = \bar{V} \, \rho.$$ I know the mean volume ##\bar{V}##, volume standard deviation ##\sigma_V##...
  27. kostoglotov

    Heading power side,do a unit in stats or computation?

    1st year, heading power side, should I do a unit in stats or "computational explorations"? My 2nd semester must needs consist of a foundations of EE unit, a foundations of ME unit, I've picked a unit for building IT systems (since a lot of power side these days involves SCADA and smart grids...
  28. J

    I Integral computation in scattering theory

    Hello everyone, Still working on my reading of Weinberg's Lecture notes on QM book. At one point, the following integral $$\int d^3 xd^3 x' V(\vec{x~}) V(\vec{x'}) / |\vec{x~} - \vec{x'}|^2$$ has to be computed in the case where ##V(r) = -e^{-r/R}/r##. This reminds me of retarded potentials...
  29. Ben Wilson

    MATLAB Fourier transform of a 2D shape

    I have a function of 2 variables [f(x,y)] where if there was an ellipse in the x-y plane, all values of the function are 1 inside the ellipse and 0 outside. I can plot this function as a surface in 3d where it looks like an elevated ellipse hovering over an elliptical hole in a sheet. My...
  30. M

    A Computation time for adiabatic evolution

    Hi, my problem: following the adiabatic theorem we get an equation for the coefficients: \dot{a}_{m}=-a_{m} \langle{\psi_{m}} | \dot{\psi}_{m}\rangle - \sum_{n \neq m} \frac{\langle \psi_{m} | \dot{H}| \psi_{m}\rangle}{E_{n}-E_{m}} exp(\int_ 0^t E_{n}(t')-E_{m}(t') \, dt') we start in an...
  31. C

    Computation of non scalar loop integrals

    Consider the following integral that comes out of a loop calculation along with some fermionic propagators (e.g virtual one loop correction to a ##p \gamma^* \rightarrow p'## process such as in DIS): $$ \int \frac{\text{d}^d l}{l^2 (l-p)^2 (p+q-l)^2} \text{Tr}(\not p \gamma^{\nu} (\not p + \not...
  32. P

    Density computation for high temperature, low pressure argon

    I am trying to compute the density of argon given the following conditions: T = 7000 K P = 21331 Pa For typical gases, I do not believe the ideal gas law would hold for such a high temp&low pressure regime, but since Argon is largely non-reactive, do you guys think using the ideal gas law would...
  33. M

    Data structure and algorithms time computation?

    Assume the following set of instructions: 1. i = 0 2. if i < n, goto line 6 3. if A [ i ] = = x, goto line 7 4. i++ 5. goto line 2 6. return false 7. return true Assume that line i take Ci time, where Ci is a constant. The worst case total time of running this block of code can be calculated...
  34. Pavkazz

    Help with Python computation to calculate age of universe

    Homework Statement I'm using python to calculate the age of the universe, by working out the distmodulus for a set of galaxys (using the V and I bands) then working out the distance in parsecs and then hubbles constant etc... I keep getting values that are 10s of magnitudes out which I assume...
  35. S

    Peskin & Schroeder - page 5 - Computation of ##\mathcal{M}##

    The following is taken from page 5 of Peskin and Schroeder. It talks about the computation of ##\mathcal{M}## for the annihilation reaction ##e^{+}e^{-}\rightarrow \mu^{+}\mu^{-}##. Even for this simplest of QED processes, the exact expression for ##\mathcal{M}## is not known. Actually this...
  36. ErikZorkin

    I Space expansion and Universe as computation

    Good day. I do not know much about cosmology, rather computer science, but the following theoretical question bothers me a little. Some scientists, like Tegmark, Wolfram, Zuse or Fredkin, support the idea that the Universe might be just computation. Computable means that something can be...
  37. T

    How can the moment of inertia of an object be calculated on an arbitrary axis?

    This seems to be a crucial detail that I just glossed over, but when finding the inertia tensor of an object, is the origin always situated at the object centre of mass? For example: In the link (http://hepweb.ucsd.edu/ph110b/110b_notes/node26.html ), is it necessary to do the integral from...
  38. Mr Davis 97

    Is computation synonymous with functions in computer science?

    So I've delved into programming, and gotten experienced with the fundamentals. However, the more I learn, the more I question the central object of comp. science, computation, and its foundation. According to Wikipedia, "Computation is any type of calculation that follows a well-defined model...
  39. EJC

    Suggestions for Quantum Computation Ph.D Program?

    I am going to be applying to grad schools in the coming months, and plan to apply to many schools. I'm looking for programs in quantum computation, quantum information, quantum optics, etc... (related research often falls under many different names). These programs generally are categorized in...
  40. hellsteiger

    Books on Quantum Logic and Computation

    Hey there PF'ers. I'm looking for a nifty book or site on Quantum logic and Computation. The sort of book like that would cover digital logic - jumps over all the explanations of underlying working and goes straight to logic and computation. I know it's important, but I have done courses in...
  41. epenguin

    Were you taught square root extraction at school?

    And what are the methods? This was stimulated by This question could be rephrased as "use the method for finding square roots you were taught in school to find √7 to 6 decimal places". If you were taught at school. If you were not taught at school you were luckier than me, I was. It has had...
  42. Breo

    A question about a computation in a paper of Effective Lagrangian

    I was hitting against a wall for the last hours. I am not able to obtain the 1/2 terms in the eq. 5 of this paper and left all in terms of only ##N_i## and ##\overline{N_i}##,neither. Anyone could give me a tip? http://arxiv.org/pdf/hep-ph/0210271v2.pdf Thank you in advance.
  43. L

    How to prove this without computation

    Homework Statement Prove: In R3if a and b are orthogonal vectors, then for every nonzero vector u, we have proja(projbu)=0 Homework Equations I know the dot product of a and b is zero The Attempt at a Solution Based on the definition of projection I eventually got to (ab) in the numerator...
  44. H

    Difficulties in the Computation of the Kretschmann scalar

    Hello, Thanks to all of you for the help that you provide so that we can move forward. I need help about the computation of the Kretschmann scalar without using software, I face to some difficulties on its computation for instance in the case of Schwarzschild metric. Could some one help me with...
  45. evinda

    MHB Computation of discrete logarithm

    Hello! (Wave) The prime number $p=67$ is given. Show that $g=2$ is a generator of the group $\mathbb{Z}_p^{\star}$. Compute the discrete logarithm of $y=3$ as for the base $g$ with Shanks-algorithm. Compute the same discrete logarithm using the Pohlig–Hellman algorithm. That's what I...
  46. Breo

    Have you conquered Peskin's computation challenges?

    Hello everyone,Has anybody already did the computations to reach equations 10.41, 10.44 and 10.45 in Peskin's book? It would be very much appreciated and useful.
  47. S

    Linear algebra -- compute the following without finding invA

    Homework Statement Homework Equations A=LU, U^-1 * L^-1= A^-1 , U^-1 * L^-1 * U^-1 * L^-1 = A^-2, The Attempt at a Solution I used MATLAB and the relations: U^-1 * L^-1= A^-1 , U^-1 * L^-1 * U^-1 * L^-1 = A^-2, to find a solution I found U^-1*L^-1 , let =B...
  48. SnakeDoc

    Slight Computation Error? Not sure what I'm doing wrong

    Homework Statement Water is poured into a container that has a leak. The mass m of the water is given as a function of time t by m = 4.9t.8 - 3.0t + 21, with t ≥ 0, m in grams, and t in seconds.(a) At what time is the water mass greatest, and (b) what is that greatest mass? What is the rate of...
  49. binbagsss

    R computation from 1 independent Riemann tensor component

    We have ##R^{1}_{212}## as the single independent Riemann tensor component, and I'm after ##R##. From symmetry properties and contracting we can attain the other non-zero components. The solution then states that ##R_{11}=R^{1}_{111} + R^{2}_{121}=R^{2}_{121}## . I thought it would have been...
  50. binbagsss

    Ricci scalar computation quick question

    Homework Statement [/B] I am trying to compute ##R## from the 3-d metric: ##ds^{2}=d\chi^{2}+f^{2}\chi(d\theta^{2}+sin^{2}\theta d\phi^{2})##Homework Equations [/B] The space also satisfies the below relationships: ##R=3k## ## R_{abcd}=\frac{1}{6}R(g_{ac}g_{db}-g_{ad}g_{bc})## [1] The Attempt...
Back
Top