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numpy

Is shared readonly data copied to different processes for multiprocessing?

August 20, 2022 by Magenaut

The piece of code that I have looks some what like this:

Categories Python, Q&A Tags multiprocessing, numpy, python Leave a comment

Rank items in an array using Python/NumPy, without sorting array twice

August 20, 2022 by Magenaut

I have an array of numbers and I’d like to create another array that represents the rank of each item in the first array. I’m using Python and NumPy.

Categories Python, Q&A Tags numpy, python, sorting Leave a comment

Why does multiprocessing use only a single core after I import numpy?

August 20, 2022 by Magenaut

I am not sure whether this counts more as an OS issue, but I thought I would ask here in case anyone has some insight from the Python end of things.

Categories Python, Q&A Tags blas, linux, multiprocessing, numpy, python Leave a comment

How to access the ith column of a NumPy multidimensional array?

August 20, 2022 by Magenaut

Suppose I have:

Categories Python, Q&A Tags arrays, numpy, python Leave a comment

Store different datatypes in one NumPy array?

August 20, 2022 by Magenaut

I have two different arrays, one with strings and another with ints. I want to concatenate them, into one array where each column has the original datatype. My current solution for doing this (see below) converts the entire array into dtype = string, which seems very memory inefficient.

Categories Python, Q&A Tags arrays, numpy, python, types Leave a comment

NumPy selecting specific column index per row by using a list of indexes

August 20, 2022 by Magenaut

I’m struggling to select the specific columns per row of a NumPy matrix.

Categories Python, Q&A Tags numpy, python Leave a comment

Using strides for an efficient moving average filter

August 20, 2022 by Magenaut

I recently learned about strides in the answer to this post, and was wondering how I could use them to compute a moving average filter more efficiently than what I proposed in this post (using convolution filters).

Categories Python, Q&A Tags filter, image-processing, numpy, python Leave a comment

Best way to join / merge by range in pandas

August 20, 2022 by Magenaut

I’m frequently using pandas for merge (join) by using a range condition.

Categories Python, Q&A Tags join, numpy, pandas, python Leave a comment

Replace all elements of Python NumPy Array that are greater than some value

August 20, 2022 by Magenaut

I have a 2D NumPy array and would like to replace all values in it greater than or equal to a threshold T with 255.0. To my knowledge, the most fundamental way would be:

Categories Python, Q&A Tags arrays, conditional-statements, numpy, python, replace Leave a comment

numpy: most efficient frequency counts for unique values in an array

August 20, 2022 by Magenaut

In numpy / scipy, is there an efficient way to get frequency counts for unique values in an array?

Categories Python, Q&A Tags arrays, numpy, performance, python Leave a comment
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  1. michealSmith07 on Is there a way to dynamically refresh the less command?August 21, 2022

    That is a very nice post. I like this post.

  2. anonymous on Fix libwacom9 dependency issue when upgrade DebianJune 27, 2022

    saved my day!! Thanks for the help…

  3. sreedhar on Fix libwacom9 dependency issue when upgrade DebianMay 10, 2022

    Thanks its working

  4. saintnick on Fix libwacom9 dependency issue when upgrade DebianMay 10, 2022

    remove libwacom2 worked for me as well

  5. ranafoul on Fix libwacom9 dependency issue when upgrade DebianApril 22, 2022

    apt remove libwacom2 helped on kali 2022.01. gr8

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