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Questions tagged [bessel-functions]

The bessel functions in mathematics are the canonical solutions of Bessel's differential equation for an arbitrary complex number.

The bessel functions in mathematics are the canonical solutions of Bessel's differential equation for an arbitrary complex number. The bessel functions can be applied in programming in various cases - when calculating pressure amplitudes, waves and vibrations, free particle and floating body dynamics, and many others.

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How can I save and reuse the results of the FFT applied on an image to calcuate the bessel potential?

Please can you help me correcting this code? I want to save the result of the Fast Fourier Transform of each image apart so I can reuse the proper coefficients for every band of wave I get from the FFT to calculate the bessel potential of the…
S. Nour
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Bessel function using scipy.quad integration not working

I'm trying to plot a Bessel function in 2D using the scipy.quad integration method. My problem: the plot only has a tiny dot in the middle because my lowest value is far too low. Here is my code: import numpy as np import scipy.integrate as…
Bobminghua
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Plotting function with a summation produces a wrong result

I have an equation that needs to be plotted, and the plot is coming out incorrectly. The equation is as follows: And the plot should look like this: But my code: clear; clc; close all; eta = 376.7303134617706554679; % 120pi ka = 4; N …
Daniel Pavlovsky
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Finding the nth root of the bessel function of the first kind (J0(x)) using bisection

First of all, I would just like to clarify that this is an assignment for school, so I am not looking for a solution. I simply want to be pushed in the right direction. Now, for the problem. We have code for finding the root of a polynomial using…
SeePlusPlus
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Arrayfire Bessel Functions

I am trying to understand the syntax of the bessel functions defined in the arrayfire documentation provided here: http://archive.arrayfire.com/arrayfire/c/group__image__func__c__bessel.htm#gaa625037807cb75ef8815051c066e9657 Under the section for …
Nathan Melton
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Advice on method to integrate Bessel functions in C++

I need to integrate an oscillatory function of this kind: where I have a Bessel function which is oscillating, while F is not very oscillatory. I am looking for the most precise/accurate method to do this in C++. Hopefully this should be an already…
johnhenry
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Integrating special function and plotting

I am trying to plot an integration of a special (eg. Bessel) function and my minimal code is the following. #!/usr/bin/env python import matplotlib.pyplot as plt import numpy as np import scipy.integrate as integrate import scipy.special as sp from…
hbaromega
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SymPy function with unevaluated argument

As a SymPy newbie, I am considering the following SymPy expression (which should be equal to 1 if 0
P. Weiss
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Handling large numbers and precision of Ricean Fading PDF python

I'm trying to calculate Ricean Fading PDF using following equation. RIcean Fading PDF. where 'y' is normalized envelope and 'gamma' is SNR if the K value is large, then math.exp(-((1.+_gamma)*pow(_y,2.) + _gamma)) exp results in big floating point…
LO_py
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How to Define a Piecewise Function in Python with Multiple Variables

I am trying to develop a plot for my helioseismology class and the question had provided a piecewise function describing the dynamics of the "fluids" in a star as if it is one thing its this and if its another its that. I am receiving over and over…
anabstudent
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Faster way to calculate bessel function in matlab

im writing a programm for a fitting routine and am currently optimizing the code for faster calculations. The weakes point is a part, where i have to calculate a big amount of bessel functions, which takes around 0.7 s. In my case q has 177 entries,…
kuy
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Roots of bessel function of first kind for negative n in Matlab

There are some codes which compute the roots of J_n(x), n > 0 I want to calculate the roots of: J_n(x), n < 0 n is a real number. Is there some algorithm or yet better some Matlab code which does this.
MOON
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3D Spherical Plot in Matlab with Derivatives and Bessel Functions

I want to plot the following function B(r,theta,phi) in spherical coordinates. Bo = 1; a = 1; % m lambda = 1; % m^-1 syms r theta; Br = 2*Bo*(a/r)*besselj(1,lambda*r)*cos(theta) Bth =…
Peter
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Improving FFT resolution - scaling Y axis

I'm attempting to plot the frequency domain of the Bessel Equivalent of an FM signal in Python. The first problem I had was improving the resolution of the FFT to enable viewing of the smaller bandwidths - I believe I have solved this by…
davidhood2
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Bessel function for complex argument in MATLAB

I'm trying to use MATLAB Bessel function of zeroth order ---> besselj(0,Z). What I noticed is: it can handle real part of nth power (say e100) but not imaginary part if it is greater than (e2) in a complex argument. Eg: (2+2*i) complex argument it…
matrix
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