Binomial coefficient
'Simple' question, what is the fastest way to calculate the binomial coefficient? - Some threaded algorithm?
I'm looking for hints :) - not implementations :)
According to the equation below (from wikipedia) the fastest way would be to split the range i=1,k to the number of threads, give each thread one range segment, and each thread updates the final result in a lock. "Academic way" would be to split the range into tasks, each task being to calculate (n - k + i)/i, and then no matter how many threads you have, they all run in a loop asking for next task. First is faster, second is... academic.
EDIT: further explanation - in both ways we have some arbitrary number of threads. Usually the number of threads is equal to the number of processor cores, because there is no benefit in adding more threads. The difference between two ways is what those threads are doing.
In first way each thread is given N, K, I1 and I2, where I1 and I2 are the segment in the range 1..K. Each thread then has all the data it neads, so it calculates its part of the result, and upon finish updates the final result.
In second way each thread is given N, K, and access to some syncronized counter that counts from 1 to K. Each thread then aquires one value from this shared counter, calculates one fraction of the result, updates the final result, and loops on this until counter informs the thread that there are no more items. If it happens that some processor cores are faster that others then this second way will put all cores to maximum use. Downside to second way is too much synchronization that effectively blocks, say, 20% of threads all the time.
- std::thread with movable, non-copyable argument
- How do I set the asyncio event loop for a thread in Python?
- Do Java 21 virtual threads address the main reason to switch to reactive single-thread frameworks?
- Migrating from Dictionary to ConcurrentDictionary, what are the common traps that I should be aware of?
- Is it possible for a C# dictionary to return a completly wrong value?
- Is my code causing deadlock ? I'm not sure. Could someone confirm or disconfirm?
- Why does thread disorder occur when the FastAPI multithread return generator?
- Is JavaScript async and await the equivalent to multithreading?
- Get the status of a std::future
- What is a race condition?
- Short but frequent jobs: HandlerThread or ThreadPoolExecutor?
- Adding NSOperation with Dependencies after a For Loop
- parallelisation of clustering method in OpenCV
- Understanding the difference between two Thread implementation approaches in Java?
- Java volatile and multithreading: what are the possible outputs for the program?
- When to prefer LinkedBlockingQueue over ArrayBlockingQueue?
- How to efficiently read and process a large file in parallel while keeping the original line order?
- Concurrent read/writes in SQLite corrupting read results?
- Does re-writing the same value to a memory location count as modifying the memory? (in the context of multi-threading)
- Thread::startVirtualThread as Threadfactory
- Why use a ReentrantLock if one can use synchronized(this)?
- Unable to load files using pickle and multiple modules
- What is the significance of 'strongly happens before' compared to '(simply) happens before'?
- How to prevent worker threads from idling until next condition variable notify
- Why is i++ not atomic?
- Submitting a callable within a callable to an Executor Service causes the program to hang
- What would it take to implement a mutex using std::atomic?
- Unable to install uwsgi Python package: can't start new thread
- How to forward a lambda function to an underlying std::thread constructor in order to execute it in a separate thread?
- If I populate a dictionary and assign it to a field - can I guarantee the field will not contain a half populated dictionary?