network profile
| bio | website | sites.google.com/site/… |
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| location | ||
| age | ||
| visits | member for | 1 year, 10 months |
| seen | Jan 9 at 14:00 | |
| stats | profile views | 20 |
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Feb 6 |
revised |
Laplace transform of the square root of a generic function introduction of a special case, and no assumption about existence of the transform. |
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Feb 5 |
asked | Laplace transform of the square root of a generic function |
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Jan 11 |
comment |
FFT for solving Poisson equation in 3 dimensions with periodic boundary conditions That's very nice I'll now be able to demonstrate the Froueri transform (whatever the definition) of $\Delta$. Thank you @Fabian. What is unclear to me is considering my practical problem and the actual definition of backward FFT in FFTW, what should I divide the forward FFT of $-\rho(\mathbf{r})/\epsilon_0$ by in order to calculate $V(\mathbf{r})$? |
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Jan 11 |
comment |
FFT for solving Poisson equation in 3 dimensions with periodic boundary conditions @Fabian corrected. Thanks. |
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Jan 11 |
revised |
FFT for solving Poisson equation in 3 dimensions with periodic boundary conditions Corrected expression of $\Delta V$ in kspace. Thanks @Fabian |
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Jan 11 |
asked | FFT for solving Poisson equation in 3 dimensions with periodic boundary conditions |
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Jul 23 |
comment |
integral of a spherically symmetric 3-dimensional function over all space As I told before ... I'm not used to deal with mathematics but I'm hunger to learn. Thanks @joriki and J.M. for your remarks. Here is the point about the values near $\vec{r}-\vec{r}'=0$: the LJ potential is also modified at small $r$, for instance using the Weeks-Chandler-Andersen scheme (this question is related to our study of perturbation theory for hard spheres thermodynamics) |
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Jul 23 |
accepted | integral of a spherically symmetric 3-dimensional function over all space |
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Jul 23 |
comment |
integral of a spherically symmetric 3-dimensional function over all space @Joriki: thanks a lot for this very clear explanation. In order to answer your very last sentence "small wonder that you've divergence": I use pair potential that converges to zero at a non-infinite radius. In fact, when people in my community say LJ potential, they mean troncated LJ potential. Sorry for the misunderstanding I should have been more careful. Thanks again I am very happy with your answer. |
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Jul 22 |
revised |
integral of a spherically symmetric 3-dimensional function over all space Changed the text in order to make clearer where my question is. |
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Jul 22 |
comment |
integral of a spherically symmetric 3-dimensional function over all space Sorry if the question was unclear: I wanted to ask if my last equation line is right (going from spherical to radial integration for a spherically symmetric function $u$). What $u$ is isn't important as this integration will be done numerically for any kind of $u$ (it's a two centers interaction potential let's say a Lennard Jones 6-12 for instance). Thank you Joriki et al! @Alice: Hi! it is indeed very linked in the sens that now that I understand this, I can understand your demonstration for my other question! Once more thank your! |
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Jul 21 |
asked | integral of a spherically symmetric 3-dimensional function over all space |
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Jul 21 |
awarded | Supporter |
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Jul 20 |
awarded | Scholar |
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Jul 20 |
accepted | Fourier (Hankel?) transform of a discrete set of radial points (question from a chemist!) |
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Jul 20 |
comment |
Fourier (Hankel?) transform of a discrete set of radial points (question from a chemist!) At first sight I misunderstood your answer because I'm not familiar with the unnormalized sinc function (thanks @Willie-Wong for the link). But your answer is exactly what I was looking for. Thank you very much @Alice! |
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Jul 19 |
awarded | Teacher |
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Jul 19 |
comment |
Fourier (Hankel?) transform of a discrete set of radial points (question from a chemist!) Thank you very much for your effort. I found the result here: casa.colorado.edu/~ajsh/FFTLog/app.ps.gz and it has been confirmed by someone else. Your formulae is not exactly true while I am not able to demonstrate it :(. The formulae for a 3 dimensional sphericaly symetric function $f$ are: $ f(k)=\int_0^{\infty} f(r)\dfrac{\sin(kr)}{kr}4\pi r^2dr$ and $ f(r)=\int_0^{\infty} f(k)\dfrac{sin(kr)}{kr} \dfrac{4\pi}{(2\pi)^3} k^2 dk$ |
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Jul 18 |
awarded | Editor |
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Jul 18 |
revised |
Fourier (Hankel?) transform of a discrete set of radial points (question from a chemist!) improved formatting |
