how can i dynamically change the value of lis so that every second it’ll output a list in which the last element is 2x the last element of the previous list . i need the output to be something like this but right now the output is I tried using global lis but that didnt work either. Answer You can
Tag: multiprocessing
multiprocessing loop over a simple list?
I have a function that calls a custom function that compares rows in a dataframe and calculates some stats. vt.make_breakpts it needs a dataframe (data), a key (unique identifier), and a datefield (date) to do it’s thing. I can run this and wait a very long time and it will go through and entire datafra…
How to access `ApplyResult` and `Event` types in the multiprocessing library
I’ve written a working wrapper around the python multiprocessing code so I can easily start, clean up, and catch errors in my processes. I’ve recently decided to go back and add proper type hints to this code, however I can’t figure out how to use the types defined in multiprocessing correct…
How to call a function periodically while my MainWindow is active?
I have tried doing it with multiprocessing module to no avail. I get the following error: TypeError: cannot pickle ‘MainWindow’ object Answer the proper way to do this is to not use any sort of parallel mechanism, instead use QTimer.singleshot, as QT doesn’t work well with multiprocessing or…
create threads within processes and share a queue between the threads
I am trying to create 3 threads within each of 2 processes and share a queue of the type multiprocessing.JoinableQueue among all threads. The worker_func function simply creates the threads while the thread_func function prints out the values it gets from the queue. The program gets stuck somewhere in the tim…
How do I uses Python’s multiprocessing.Value method with .map()?
I’m testing some code using multiprocessing to try to understand it, but I’m struggling to get the .Value to work. What am I doing wrong, it says p doesn’t exist? here’s my code: And I get this error: What should I do? Answer You only want a single instance of the shared value, p, to b…
How can I parallelize a function with multiple arguments
I have written a function create_time_series(input_df1, info_df1, unit_name,start_date,end_date), which aims to create a time series based on log-files saved in input_df1. The problem of my function is that the execution is slow, therefore I thought of parallelizing it. The following code is my attempt at uti…
Python Process Pool with custom Process not able to respawn child processes
I have overridden multiprocess.Process (fork of multiprocessing library) like so: When I create normal Process using this class everything works perfectly, including creating logs. Now I want to create a Process Pool of such customized processes but I encountered problem with respawning such processes after t…
Multiprocessing where new process starts hafway through other process
I have a Python script that does two things; 1) it downloads a large file by making an API call, and 2) preprocess that large file. I want to use Multiprocessing to run my script. Each individual part (1 and 2) takes quite long. Everything happens in-memory due to the large size of the files, so ideally a sin…
Share RLock between multiple instances of Python with multiprocessing
Consider this MWE: When this script is executed, it instantiates the_setup and serves it. Then I want clients to be able to do things like this from other scripts: However, I get RuntimeError: RLock objects should only be shared between processes through inheritance. If the with the_setup.hold_hardware(): is …