Questions tagged [numpy]
NumPy is the fundamental package for scientific computing with the programming language Python.
765 questions
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Finding the closest point to a list of points
I'm trying to find the closest point (Euclidean distance) from a user-inputted point to a list of 50,000 points that I have. Note that the list of points changes all the time. and the closest distance ...
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Sending a C++ array to Python/NumPy and back
I am going to send a C++ array to a Python function as NumPy array and get back another NumPy array. After consulting with NumPy documentation and some other threads and tweaking the code, the code is ...
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Backpropagation in simple Neural Network
I've been working on a simple neural network implemented in python. Currently, it seems to be learning, but unfortunately it doesn't seem to be learning effectively. The graph below shows the output ...
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Crop black border of image using NumPy
Objective: Crop the image so only the number stays in the image
Problem: Slow Performance
I have code that crops an image.
The image pixels are 0 or 255. There are no values between.
The ...
user108668
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3
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Remove points in a straight line
I wrote this code to remove points that create a straight line when plotted.
For instance, this has many points in a straight line:
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Scale Numpy array to certain range
As I've described in a StackOverflow question, I'm trying to fit a NumPy array into a certain range.
Here is the solution I currently use:
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- 1,617
21
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1
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Remapping and interpolating 255x1024 array
I have a function that accepts a \$255\times1024\$ array and remaps it to another array in order to account for some hardware related distortion (lines that should be straight are curved by the lens). ...
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Processing an image to extract green-screen mask
I am using OpenCV to process an image, and in my code, I have to check / edit each pixel separately:
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Pretty printing of the numpy ndarrays
Following this idea for pretty printing of numpy ndarrays, I have developed a very primitive prototype:
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Finding a zero crossing in a matrix
I am trying create an algorithm for finding the zero crossing (check that the signs of all the entries around the entry of interest are not the same) in a two dimensional matrix, as part of ...
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Fastest way to iterate over Numpy array
I wrote a function to calculate the gamma coefficient of a clustering. The bottleneck is the comparison of values from dist_withing to ...
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Plot timings for a range of inputs
When writing Code Review answers, it becomes often necessary to measure how long the modified code takes vs how long the OP's code takes. I needed a nice way to visualize this as a function of the ...
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Warhammer: How many of my attacks will succeed?
Me and a couple of mates sometimes play a game called Warhammer.
When playing the game you have options of what each model attacks.
This can lead to situations where you know if you shoot with 100% of ...
- 44.6k
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Efficiently selecting spatially distributed weighted points
Background:
Motivation behind writing the following code is originated in the area of computer vision. More specifically – image rectification. In order to obtain rectified images, one has to find a ...
- 1,997
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Solve the phase state between two haplotype blocks using markov transition probabilities
I have spent about more than a year in python, but I come from biology background. I should say I have got some understanding of for-loop and nested-for-loop to workout the solution to the problem I ...
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