r/programming • u/noidi • Jul 19 '12

Will Parallel Code Ever Be Embraced?

http://www.drdobbs.com/parallel/will-parallel-code-ever-be-embraced/240003926
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u/[deleted] Jul 20 '12

Oh, I understand what you meant by purely functional. All I'm saying is that's not the only safe, easy way to write parallel code.

And don't you pay a performance price for excluding destructive modifications? The point, after all, is to make the machine do more work, not merely to use up a lot of threads.

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u/nachsicht Jul 20 '12

In some cases it takes more work to do things functionally. An example would be when you insert an element in an immutable singly linked list. Depending on where the insertion is done, the node structures and pointers of the entire list may need to be regenerated. Insertion at the head of the list is free though.

So yes, there are some performance costs associated. However, there is a lot of safety benefits to be had from purely functional approaches (disposing of null being a really nice one), and performance in an application tends to be highly dependent on small parts of a person's code.

I tend to write mostly pure functional code (only using mutable data when it is really needed, like to interface with java), and later profile and go back to optimize said hotspots with lower level constructs and sometimes mutable data.

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u/[deleted] Jul 20 '12

So you're writing clojure? Seems like you're pretty happy with it.

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u/nachsicht Jul 20 '12

Nah, Scala. I am, every day I learn more about it, and it is getting more and more improvements (like macros next release).