115,292 questions
1
vote
1
answer
15
views
NumPy generate a 2d linear array using multiple values
So I'm trying to generate a map for a personal project using opensimplex noise, multiple layers etc.
My problem is that I want to recreate the equator to combine with a temperature map to obviously ...
- 738
Best practices
1
vote
1
replies
30
views
Create mask from array based on threshold
I have an array and I want to create a mask for this array based on a threshold, sorry if the explanation is a bit convoluted.
The first step is to find the intervals of elements higher than half of ...
- 412
1
vote
0
answers
56
views
Numpy importing error in mod_wsgi app on Fedora 43
I'm getting an error when importing numpy from an Apache mod_wsgi application on Fedora 43 and 42. It does not happen in Rocky Linux 9, the production server.
app.wsgi:
import sys
sys.path.insert(0, '/...
- 127k
4
votes
1
answer
83
views
Efficiently coercing a Python list to a Numpy array with a custom datatype
I am using python to build an OpenGL rendering engine and am using numpy arrays with a custom datatype to store my vertex data.
import numpy as np
data_type_vertex = np.dtype({
"names": ...
- 43
0
votes
0
answers
57
views
Why am I getting a blank nullcline plot? [closed]
I'm trying to plot nullclines for a nonlinear system and determine fixed points from the same. However, until now, my code has not been good enough to generate the plots. Presently, I'm only able to ...
1
vote
1
answer
54
views
What is the correct NumPy representation of a row vector for gradients
I am doing an assignment on matrices and gradients, where the final answer must be expressed as a row vector.
vr = np.array([1, 2, 3])
vrr = np.array([[1, 2, 3]])
Mathematically, a row vector should ...
- 11
Advice
2
votes
5
replies
95
views
Numpy handling small imaginary parts differently
There is a difference in behaviour on macOS with arm64 CPU vs other Linux with amd64.
For numpy v1 on arm64, it seems there is an internal logic guaranteeing the imaginary part to be exactly 0:
>&...
- 302
2
votes
1
answer
66
views
How do I make a custom field output different datatypes depending on file asking for data?
I'm building a molecule properties displaying website using django and sqlite. The database takes a numpy array and stores it as a BLOB. Currently, it just outputs the numpy array back out when asked ...
- 31
0
votes
0
answers
93
views
Noiseless Gaussian Process Regression not crossing the training points
I'm trying to perform a Gaussian Process Regression on series of data points Y and ln(X+(10^-4)) (The X values are used in log scale to create the model)
X ln(X+(10^-4)) Y
0.00001 -9.11503019 ...
- 1
2
votes
1
answer
33
views
How do I fix a "TypeError: bad number of pixels" in a healpy.fitsfunc.write_map call?
I have downloaded the HEALPix5 DECaPS 3D dust extinction map (from arXiv:2503.02657) and imported it as a numpy array meanmap. The array gives an expected result (51415400, 1, 120) to the meanmap....
- 21
2
votes
1
answer
115
views
numpy 2.2.6 tries to build on Windows 11 x64 instead of using wheel
originally I was trying to install opencv-python which fails on trying to install numpy:2.2.6
So I am trying to just install this numpy and for some obscure reason it tries to build it! instead of ...
- 1,584
3
votes
3
answers
107
views
Numerically finding the minimum value of a variable where a function equals a value
I have a black box function baseball that determines the magnitude of the distance that a baseball travels when launched. It takes the initial speed, the angle of launch and the initial spin. Assuming ...
- 47
1
vote
1
answer
92
views
Scipy Hessian with Numpy cross product
I need to compute the Hessian of a function involving cross products in Python. As an experiment, I consider the simple function
def func(x):
return np.sum(np.cross(x[0:3], x[3:6]))
and compute the ...
- 153
1
vote
0
answers
66
views
PSTH with numpy.histogram shows periodic “gaps” at bin boundaries even after integer time conversion—how to bin robustly?
I’m computing peristimulus time histograms (PSTHs) in Python. Each trial aligns spikes to a reach-start timestamp and bins them into fixed-width bins. I see vertical “gaps” (low counts) at exact bin ...
- 11
0
votes
1
answer
47
views
Creating 3d Mesh from Z stack of ROIs
I have a set of 3D ROI label stacks stored as TIFF files, where each ROI represents a single cell. I want to generate surface meshes(I use trimesh) suitable for downstream shape analysis.
I tried ...
