Questions tagged [python]

A general purpose high-level programming language that emphasizes ease of code syntax and readability.

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How to implement tolerance checking within a for loop whilst performing a numerical integration using a trapezoidal function?

Currently, I have this working code where I have been able to successfully calculate the integration for standard results. But in terms of precision, how could I achieve a good tolerance? ...
69 views

Newman algorithm yielding different result to what is given in his paper

Summary I am trying to implement Newman's algorithm for community detection, outlined in this paper. I am testing my implementation against one of the datasets used in that paper to benchmark the ...
306 views

Solving an ODE using odeint in Python and continuing the integration

The following relates to the linked question: Scattering of waves in a symmetrical potential (using python) I have attempted to solve the problem for $U(r)$ using ...
199 views

How to change the value of a variable at some point lying in the time interval of solver in solve_ivp

The following code solves a differential equation with scipy: ...
781 views

How can I evaluate more accurate energy eigenvalues from Schrodinger equation using shooting method?

I am trying to use the "shooting method" for solving Schrodinger's equation for a reasonably arbitrary potential in 1D. But the eigenvalues so evaluated in the case of potentials that do not have hard ...
22 views

Python: Getting second output variable from minimizing a computationally intensive function on first outputs

I have a function in python that is quite computationally expensive to evaluate, of the form: ...
756 views

solve_ivp - Overflow encountered in double_scalars

I'm modeling an electron that orbits the nucleus. Of course, charged particles radiate away there energy so it'll crash into the nucleus. My approach has been to to evaluate the coulomb force and add ...
315 views

How to implement Simpson's rule for double integral (without numeric limits of first integral)

I want to use Simpson's rule to evaluate the following double integral: $$\int_{a}^{b}\left|\int_{0}^{z}x\cdot \mathrm{erf}(x-10)\cdot J_{0}(x) \mathrm{dx}\right|^{2}\exp(-0.5*(z-40)^2)\mathrm{dz}$$ ...
71 views

Scipy.integrate.odeint is returning curves with almost the same frequency for different damping ratios, shouldn't they be different?

I am trying to solve the ODE for a harmonic oscillator using Scipy's odeint solver for different dampening factors. I'm using the following code, based off of this example: ...
420 views

Coding of the Legendre polynomial and the infinite sum using python

I'm looking to code the following function: $$|g(\theta)=\frac{1}{2k}\sum_{\ell=0}^{\infty} (2\ell +1)\sin(2\delta_{\ell})P_{\ell}\cos(\theta)|^2$$ ...
84 views

Distributed computation with computers around me

I know for large amounts of data there are online computation services or supercomputers or Beowulf cluster. For a small quantity of data, a good computer is enough. But sometimes, for medium qty of ...
446 views

32 views

SHREC 2010 Descriptors

I will appreciate if I may find someone how can clarify for me the part regarding the quality of feature descriptor, shown in the figure below: and this screenshot is from the article: SHREC All my ...
464 views

Fastest Way to Mutiply $10^4$ 2x2 Matrices

In a code that I work with (written in python, but also tagging as matlab because numpy is so close and I could use it if need be), we use a transfer matrix method to compute the properties of a ...
283 views

Solving ODE with "Jumpy" Coefficients

I'm numerically solving a linear coupled ODE of the form $$y^{\prime}(t) = \hat{M}(t)y(t)=\left[\begin{array}{cc}0& A(t)\\ B(t)& 0\end{array}\right]y(t),$$ and the difficulty I'm running into ...
33 views

sequence\ flow analysis with score- beginner data scientist

I'm trying to create a model that will give me the best parts that lead to a maximized score out of a sequence. my data(spark rdd) looks like this: ("dan", "john", "john", "guy", 45) ("john", "dan",...
169 views

Evaluate 3D Shape Descriptor

I'm trying to create my own 3d shape descriptor, the idea is that how I may evaluate how much my descriptor is well and good? What I checked is that they evaluate descriptors through shape matching, ...
8k views

Solving coupled differential equations in Python, 2nd order

I have a system of coupled differential equations, one of which is second-order. I am looking for a way to solve them in Python. I would be extremely grateful for any advice on how can I do that! $k$...
54 views

How do I graph this in python? [closed]

$$y=\cases{-\sqrt{|x|}, \quad x\le0\\\sqrt{x}, \quad x>0}$$ I've tried graphing this in python, but can't seem to figure it out. Does anyone know how to do this by chance?
161 views