Questions tagged [multiprocessing]
Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system.
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Showcase difference multiprocessing and threading in Python
This week I dived into the issue of speeding up my program by either threading or multiprocessing. I did not understand well the difference between the two, but that became quite clear when I got the ...
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Running an Excel Macro from a Child Process Using Multiprocessing Cannot Access Excel Object in Main Process
First, some background on what I am actually trying to do here: I am trying to open an Excel Workbook from Python, then run certain macros within that workbook, but with a timeout feature, so that, if ...
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1answer
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Thread-safe running mean and variance
In one of my personal python libraries I have a custom class used for computing the running average and variance of a stream of numbers:
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Nearest neighbor search algorithm of quantization
I'm doing some research on Nearest Neighbor Search of quantization, where running speed is very important. As I've just started using Python, I wonder if the following code for multi-processes can be ...
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Subclass of Python's multiprocessing.Pool which allows progress reporting
For context, the whole of the project code can be found here. This question was created specifically for the progress.py file.
The goal behind it is to allow ...
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1answer
46 views
Multi-core OpenCV denoising
I have ~40,000 JPEG images from the Kaggle melanoma classification competition. I created the following functions to denoise the images:
...
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130 views
PyQt load images in background process
I am building an application that needs to load 100-200 images (really only limited by performance) and display them to the user in a sort of gallery. A good analogy would simply be Google Images. In ...
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1answer
50 views
benchmarking requests to localhost
I am writing a benchmarking tool from scratch in Python.
However I can't get the performance of other benchmarking tools like wrk or ...
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1answer
827 views
Compute the outputs of a generator in parallel
I am processing an unknown "length" of generator object.
I have to keep things "lazy" because of memory management.
The processing is compute heavy, so writing it multiproc style ...
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Python/Mongo - Generating dummy data
I wrote below piece of code generating dummy data loaded to MongoDB.
2 issues :
1.customer class has subscriber class so it nested with one level customer--> subsciber.
I think i'm not doing right:
...
3
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0answers
119 views
Assigning parallel workers to predict from keras model using concurrent.futures
I am working on a Reinforcement learning project, where I have to gather a lot of data using a TensorFlow model. During the data gathering, the weights of the model do not change. So, I am using ...
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1answer
42 views
Hardware driven data processing and ploting in need of better control flow
This is code for a measurement setup that receives a steady stream of UDP data, finds the trigger in one channel and operates on the data in the other channel to enhance the signal and remove noise, ...
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0answers
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Implementation of Policy Gradient Reward Design paper
I've implemented the first experiment from the Reward Design via Online Gradient Ascent paper. I don't have any specific concerns, but it's my first time using multiprocessing or doing reinforcement ...
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How can I reduce the TIme Complexity. of the python program
I have 7000 CSV files that I want to do operation on. but the problem is that it takes to much time like it takes 13 seconds to process these files.
What I need to know is which operation take more ...
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1answer
2k views
python flask spawn jobs with multiprocessing
I have a python flask app that waits for requests from user app and than spawns a process with job based on the request it receives.
It keeps the status and queue of the jobs in memory.
The requests ...
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3answers
110 views
Analysing a Huge Codebase with Python
I've written a Python program to analyse a huge C++ code base in excess of millions of lines of code. The job of the program is simply to search for all C and C++ style comments and extract all the ...
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1answer
74 views
Divide and Conquer Password Bruteforcer
My program brute-forces a password. The password is a string composed of a key and a four digit numeric code. The key is known so we are basically brute-forcing between 0000 through to 9999
An example ...
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2answers
174 views
Class with multiple workers
I am building a tool that interacts with a batched stream of incoming data. This data needs to be processed and the result returned. To split up the work I have created a class that has inbound (...
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1answer
85 views
Parallel image segmentation [closed]
Follow up question Image processing using Python OOP library
I want to use multiprocessing to analyze several images in parallel:
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1answer
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Python code refactor to use multiprocessing [closed]
I have written some Python code that opens files one by one, does some work, and writes data onto the filesystem. I figured, I want to make use of my cores.I've refactored the program into this.
<...
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1answer
25 views
Join ArcGIS tables in Python of plant greenness in response to prior month's rainfall
I am using Python 3.8 with ArcGIS Pro 2.5. This code creates a joined table where I match values for plant greenness in the current month with rainfall X number of months into the past. Each loop ...
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1answer
72 views
Data segmentation and optimization for Multi-threaded/Multi-core use (In Python)
I have written a very basic algorithm, that counts the amount of times sub-string appears in a string.
The algorithm is given:
seq - a string sequence
k - length of a sub-string
L - a window of a ...
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0answers
50 views
Monitored parallel mapping across a Pandas dataframe
This code maps a function over a dataset in parallel in a monitored fashion, and returns the result in the variable out.
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1answer
83 views
Create 1% Sample Using Multiprocessing in Python
I'm trying to process a large dataset (300GB, myfile.txt in the script) line by line using multiprocessing. I want to define a 1% random sample based one variable (contained in unique_ids_final.txt). ...
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1answer
76 views
Plot timings for a range of inputs MkII
To celebrate questions getting more reputation points per upvote, I revisited my previous question, Plot timings for a range of inputs.
Since the time of that original question (more than two years!),...
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2answers
970 views
hash image url and if valid store image url
I am trying to get all image urls which are valid and unique.To make sure i wont end up using the same image again i calculate hash of the image and store it in a text file and read the text file ...
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1answer
133 views
Gamblers ruin, parallel compute trials
Context
The following script is a quick implementation of the gambler's ruin problem. For each given upper bound on the number of rounds in a game max_iter, ...
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1answer
49 views
Monitor a web page for when a desired price is met
I have a code that keeps checking a webpage with a price on it and when the price meets a number I set it to, the thing is purchased. I am looking for ways to increase the speed of it.
I have added ...
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1answer
197 views
Simple sharding of delimited files to more sophisticated
A while back I came across the issue of having a large delimited file where I wanted to simply parallelize my python code across each line of the file. However, doing so all at once either took up too ...
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2answers
676 views
Parallelized for loop in Bash
I am using a Bash script to execute a Python script multiple times. In order to speed up the execution, I would like to execute these (independent) processes in parallel. The code below does so:
<...
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540 views
First readers-writers problem using a single condition
For the first readers-writers problem, in which readers can access a given resource simultaneously, is the following Python3 solution correct?
Problem parameters:
One set of data is shared among a ...
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0answers
952 views
Image processing using multiprocessing in Python
I have an image stack. I am trying to use multiprocessing to do some process on each image in stack to get new image, and then bitwise_or with the old image.
Since ...
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0answers
128 views
A Parallel Processing Template for Divide & Conquer Problems
I’ve written a program for solving a problem using standard single-threaded code. However, it looks like it could be recast as a multi-threaded problem using divide & conquer. Since this is a ...
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1answer
1k views
Python 3.7 UltimateBruteforcer
So I made a bruteforce program for sha-X hashes and MD5 using wordlists in Python.
I know Python is probably one of the worst languages for this, but it's only for learning purposes.
I think this was ...
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0answers
46 views
Python process-subprocess communication
I have two processes. First (main) one is "dealing" with user stuff. Second one is doing some internal stuff and should update its internal state according to user actions. So I've created two pipes. ...
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2answers
706 views
Translate nucleic acid sequence into its corresponding amino acid sequence
Goal of the program
The goal of the program is to translate a nucleic acid sequence into its corresponding amino acid sequence. The nucleic sequences
have to be formatted in a specific format called <...
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2answers
283 views
Implementing lock within a Python script
I've written a script in Python using multiprocessing to handle multiple process at the same time and make the scraping process faster. I've used locking within it to prevent two processes from ...
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2answers
1k views
Extract name, address and phone number from some web pages using multiprocessing
I've written a script in Python using the multiprocessing module to scrape values from web pages (one page per subprocess). As I'm very new to ...
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0answers
335 views
Using Perl's fork() to parallelize processing
I use bash scripts to process last names through a Perl program, and I parallelize the execution like this, by name initials:
...
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1answer
63 views
GET multiple data frames using external module's function that uses requests
Purpose
The point of this mini project is to quickly gather data from a website's API and combine the collected DataFrames into a "master" DataFrame with all of the stocks I am interested in looking ...
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2answers
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Python worker pattern for multithreading
I'm building a script where I pass in a text file of hostnames, and a text file of commands and each command will then be run against each host.
To prevent this getting out of hand I'm also passing ...
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1answer
66 views
Count features in a file, using parallel code
When processing large files (say for parsing or performing computations based on the contents), we want to be able to use multiple processes to perform the job faster.
In my case I wanted to count ...
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1answer
4k views
Passing shared memory array to worker pool in Python
I'm working with big 2d numpy arrays, and a function that I need to iterate over each row of these arrays.
To speed things up, I've implemented parallel processing ...
3
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0answers
31 views
Architecture for a parsing tool
PostgreSQL, Python 3.5, SQLAlchemy
I have a main database which has a journals table containing 30k+ journals. For each journal I have a RSS feed URL, using which I can parse and get new articles. ...
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2answers
283 views
Parsing contents of a large zip file into a html parser into a .csv file
I have some zip files somewhere in the order of 2GB+ containing only html files. Each zip contains about 170,000 html files each.
My code reads the file without extracting them,
Passes the ...
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0answers
213 views
Python multiprocessing for tasks depending on each other
I have a simulation that runs a process on a tree structure, where the slow processes down processes are separate from each other. This looked like a thing that would be a prime candidate for ...
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1answer
267 views
Add an edge to a graph to minimize the average shortest path length
This program is used to find the nodes in a grid network, between which, if an edge is added, the average shortest path length of the entire grid reduces by the most.
"Average shortest path length" ...
3
votes
1answer
394 views
Genetic algorithm to find the minimum of a three-variable function
I've implemented a simple genetic algorithm for continuous floating point parameter spaces and without recombination. However, the way I'm passing in parameters and acquiring results from ...
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vote
2answers
19k views
Loop through a list of URLs multi-threading and check return code in python
I have to loop through a list of over 4000 urls and check their http return code in python.
Url.txt: Contains a list of 4000 urls with one url per line.
The script takes a long time to run and I ...
