Questions tagged [multiprocessing]
Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system.
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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). ...
3
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1answer
42 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
77 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 ...
5
votes
1answer
93 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, ...
3
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1answer
43 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 ...
3
votes
1answer
140 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
524 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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0answers
278 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
268 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
99 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
37 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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votes
2answers
649 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
262 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 ...
2
votes
2answers
328 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 ...
3
votes
0answers
166 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:
...
3
votes
1answer
47 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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votes
2answers
955 views
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 ...
2
votes
1answer
50 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 ...
2
votes
1answer
3k 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. ...
4
votes
2answers
150 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 ...
2
votes
0answers
74 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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votes
1answer
137 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" ...
4
votes
1answer
357 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 ...
1
vote
2answers
14k 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 ...
4
votes
1answer
287 views
Subprocess CSV validator and multiprocessing on Python
This Python script takes a directory of CSV files and calls a Scala script which tests whether a file's contents match a given regular expression. The link to this Scala script can be found in the 3rd ...
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0answers
1k views
Python script to generate a playlist with the Spotify API
The result is just a list of youtube links.
I'm requesting an access token every time and throwing it away, so I'm thinking of a way to save it for future use. Maybe I'll use a tempfile, but even ...
4
votes
1answer
515 views
Creating a graph representing all combinations of 4-bit binary strings
Update: Important notes to understand the problem can be found in the comments under the response of colleague Gareth Rees's.
I have an algorithm that creates a graph that has all representations of ...
2
votes
1answer
286 views
Pipe based multiprocess filter
This code is a multi-threaded version of filter that uses pipes to communicate between the workers and the main thread. I am looking for any ways to make this code cleaner. I'm also interested in if ...
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votes
0answers
105 views
Concurrency using immutability
I was watching the following video about software transactional memory(using a package that maintains an access log). At the moment I am trying to learn about concurrency with shared memory and ...
6
votes
3answers
230 views
Class scheduling tool with image output
I have a multilayered dictionary that contains information about classes. I am using this to code an automatic schedule builder that I will eventually add to a separate Tkinter application I made that ...
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vote
0answers
788 views
Load balancing consumer and producer with multiprocessing
Tasks are distributed to producer in multiple worker process. Results from workers are sent through Queue to a ...
11
votes
1answer
260 views
Using Support Vector Machine algorithm to analyze satellite image [closed]
I am using Support Vector Machine (SVM) algorithm to perform a classification. The satellite image I am using is really big (5GB) that's why I am trying to take advantage of ...
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0answers
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Watchdog for multiprocessing
The code shows here is a demo of my application. The func1 always hang somewhere with reason I haven't figured out by now. Now I just want to write a watchdog for this process. If it didn't generate ...
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0answers
621 views
Python multiprocessing with multithreading - processing a list of work
Although this code can be used for many different purposes, I'm building it for use in web-scraping. I would like to know if this is the best approach. Can you see any bugs or potential lockups?
The ...
4
votes
1answer
80 views
Simple Bash Parallel Tool (env_parallel dies on big env)
This is a simple tool to parallelize execution of multiple tasks in Bash, since env_parallel can't handle the environment size (or something of the sort - dies for ...
6
votes
2answers
14k views
Faster brute force algorithm
I have this brute force code, where you input a password and runs through combinations of numbers, lowercase and uppercase letters, and special characters until it match the password given.
The ...
6
votes
2answers
227 views
~600k external API requests for uploading part numbers to an inventory
I have a CSV containing ~600k part numbers to be uploaded to my website's inventory. However, this CSV only contains limited information. We're missing pricing and other related information. To get ...
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1answer
10k views
Python Executer that kills processes after a timeout
Imagine you want to run a bunch of tasks in parallel, but you can't be sure that all of your tasks will eventually terminate or rather decide to eat up all your memory and CPU time. This should be ...
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votes
0answers
50 views
VIM colors downloader in Python, using multiprocessing
I recently posted this script:
VIM colors downloader in Python
But since I'm not allowed to update the code there, I wanted to get an idea on this version, that uses multiprocessing:
...
3
votes
1answer
466 views
Erlang process pool
I am coming from Java and I am trying to create a process pool in Erlang.
Like the Java API:
...
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vote
0answers
73 views
Using RemoteChannels for an parallel iterable map
RemoteChannels hit with julia v0.5
There are no examples online, but I managed to get them to work.
They are still very new, and all this whole area of multithreading code continues to have running ...
5
votes
1answer
41 views
Fetch data from co-processor on network in background
My code communicates with a Raspberry Pi (with a static IP address) running on a network. The client sends a signal to the Pi, and the Pi sends back a double (encoded as a string) with the angle ...
4
votes
2answers
5k views
Multiprocess, multithreaded read write on a single file
I've got a job to create a library that would be able to support multithreaded and multi process read and write to a single file. On that single file we would store C# models in an array in JSON ...
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votes
0answers
32 views
Adaptive scan of function concurrently
This function try to scan the given function in n dimensions in the given range by adaptively divide the area into n+1 points polygon (e.g. triangle in 2D; tetrahedron in 3D)
I tried to seperate the ...
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0answers
299 views
Optimal use of Python 3's multiprocessing package to create Sudoku grids
I want to create Sudoku grids using Python. As it's pretty slow if I want to create a bunch of grids, I decided to use multiprocessing.
My computer has 4 virtual ...
2
votes
2answers
2k views
Using doParallel to cycle through *.rds files
Overview
I have 165,000 *.rds files that are around 200,000 obs x 13 variables each. These files are unique to grid files (2.5 square mile data) so I need to keep them in their unique grid numbers. ...
2
votes
2answers
15k views
Blocking until condition is met
I have a class called _NodeProcess. It consists of a mainloop (main function) which is run in a separate process and methods (<...
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votes
2answers
216 views
Asynchronous model fitting that allows termination in Python
The problem
When you work with Python interactively (e.g. in an IPython shell or notebook) and run a computationally intensive operation like fitting a machine-learning model that is implemented in a ...
