Questions tagged [numpy]

NumPy is the fundamental package for scientific computing with Python.

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5
votes
1answer
3k views

Logistic regression with Python

I am trying to code up logistic regression in Python using the SciPy fmin_bfgs function, but am running into some issues. I wrote functions for the logistic (...
1
vote
0answers
77 views

Calculate integrals using numpy.fft

Good evening, I would like to understand why I do not get the correct result: I assume that I know my function on discrete data points and expand it as a discrete Fourier transform: $\text{sin}(x)=\...
14
votes
3answers
2k views

How to express this complicated expression using numpy slices

I wish to implement the following expression in Python: $$ x_i = \sum_{j=1}^{i-1}k_{i-j,j}a_{i-j}a_j, $$ where $x$ and $y$ are numpy arrays of size $n$, and $k$ is a numpy array of size $n\times n$. ...
3
votes
1answer
665 views

My calculated laser pulse duration is too large. Where am I wrong?

I am currently writing a small Python script to estimate the pulse duration from the optical spectrum. At the end, the idea is to observe the effects of the spectral phase on the pulse duration and ...
1
vote
2answers
337 views

Numpy FFT gives me a pulse shorter than it should be. Not sure what I am doing wrong

I've created a code (Python, numpy) that defines an ultrashort laser pulse in the frequency domain (pulse duration should be 4 fs), but when I perform the Fourier Transform using DFT, my pulse in the ...
0
votes
1answer
158 views

Is it possible to partition 2D data into bins such that each bin contains the same number of samples?

I am trying to sort data following a bivariate distribution into a numpy histogramdd, where each bin should contain the same number of data points (to the nearest whole sample). I expect that some ...
0
votes
1answer
740 views

roots of polynomials of high degree: LinAlgError: Eigenvalues did not converge

I wrote a simple script to generate random polynoimals $\displaystyle f(z)= \sum_{k=0}^N a_k \frac{z^k}{\sqrt{k!}} $ of high degree and find their roots. For more discussion on random polyomials see ...
0
votes
1answer
6k views

Python Finite Difference Schemes for 1D Heat Equation: How to express for loop using numpy expression

Hello all, I've recently been introduced to Python and Numpy, and am still a beginner in applying it for numerical methods. I've been performing simple 1D diffusion computations. I suppose my ...