Questions tagged [multiprocessing]

Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system.

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3
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1answer
39 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
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1answer
128 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 ...
11
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2answers
512 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
70 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 ...
1
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0answers
121 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 ...
5
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0answers
88 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 ...
10
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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 ...
1
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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. ...
14
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2answers
643 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 <...
5
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2answers
259 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
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2answers
195 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
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0answers
136 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
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1answer
46 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 ...
9
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2answers
527 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
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1answer
47 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
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1answer
2k 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
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2answers
138 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
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0answers
63 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 ...
6
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1answer
123 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
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1answer
309 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 ...
0
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2answers
12k 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
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1answer
252 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 ...
5
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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
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1answer
497 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
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1answer
268 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 ...
3
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0answers
103 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
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3answers
224 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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0answers
713 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
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1answer
236 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 ...
1
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0answers
938 views

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 ...
2
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0answers
602 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
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1answer
78 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
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2answers
13k 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
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2answers
219 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 ...
14
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1answer
9k 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 ...
3
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0answers
49 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
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1answer
427 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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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
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2answers
4k 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 ...
2
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 ...
1
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0answers
291 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
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2answers
1k 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
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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 (<...
3
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2answers
185 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 ...
1
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0answers
629 views

Simple distributed lock manager server based on zmq

I wrote a simple server to distribute locks on a network. It is used in a multi-server environment with a shared home directory to secure non-multiprocessing safe file writing (...
6
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1answer
140 views

Multiprocess Bogosort

I only program by hobby, and I'm trying to improve with Python, so along with practicing coding I decided to venture into multiprocessing. This is a command line and will sort a variable number of ...
7
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2answers
959 views

Extracting keywords from 3 billion CSV records

I am processing around 3 billion records using this piece of code. It's pretty slow; it would be really helpful if you could suggest better ways to do this. ...
7
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1answer
5k views

Fast Thread- and multiprocess-safe file operations in python under Linux

I'm trying to implement an alternative to python built-in open(), but safe for use in multi-threaded and multiprocessing environment. I'm using advisory locking, ...