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Re: Function Points

From Paul Rubin <no.email@nospam.invalid>
Newsgroups comp.lang.forth
Subject Re: Function Points
References (15 earlier) <boCdnWK73KpVIKbNnZ2dnUVZ8kednZ2d@supernews.com> <7xd32bx1fj.fsf@ruckus.brouhaha.com> <ZP2dnVxfr6yk4aHNnZ2dnUVZ8iWdnZ2d@supernews.com> <7xk3wjujt3.fsf@ruckus.brouhaha.com> <KICdna57R5BSYaHNnZ2dnUVZ8jGdnZ2d@supernews.com>
Date 2012-08-28 23:05 -0700
Message-ID <7x4nnmw7vj.fsf@ruckus.brouhaha.com> (permalink)
Organization Nightsong/Fort GNOX

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Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>>In Haskell, memoization is done with lazy evaluatio
> Well, yes, so you use STM for memoization.  Where, exactly, is the
> problem?  I must be missing something.

Hmm, maybe you're right; I'm not sure.  There is a potentially bad
performance bottleneck with STM if there's a big memoization table that
you're updating a lot of parts of simultaneously from different threads.
GHC's approach relies on the immutability of values in Haskell, so two
threads might update the same cell with no locks, but it's with the same
value so it's ok.  I guess you could also write imperative code that way
though, so I'll have to ask the #haskell folks if there's more to it
than that.  I know there has to be some special hair in GHC's garbage
collector for it, but maybe it's less of a big deal than I thought.

> I wouldn't have thought so: [Cilk] fork/join is for computations that
> can be partitioned in some way.  Of course, the partitioning has to be
> correct.

By comparison, Haskell's "par" annotations can be inserted anywhere in a
program with no effect on the computed result.  If you choose
un-judiciously where to put them, you might get a slowdown instead of a
speedup, but you won't introduce weird bugs.  There is a cool tool
"ThreadScope" that shows how much parallelism actually results, so you
can tune it.  I think Cilk might have something similar, though.

> To the extent that functional-style data structures make sense, yes,
> of course.  I presume "functional-style" means write-once or some kind
> of copy on write, which is well established.

Yes, a classic example is using AVL or red-black trees instead of hash
tables for associative maps.  The idea is you can "copy" an AVL tree
while adding or deleting a value in O(log n) operations, with the new
tree sharing most of the old tree's structure.  There's a good book
"Purely Functional Data Structures" by Chris Okasaki with more examples.

> AFAIK functional languages have no advantages over imperative
> languages in the area of concurrency except the aforementioned
> checking.

Of course functional languages are implemented with imperative machinery
under the hood, so with enough effort you can always write imperative
code that does the same stuff as functional code.  FPL's just make
writing parallel code safer and more convenient, which actually does
matter quite a lot of the time.

Did you ever look at Tim Sweeney's slides about future programming
languages?  I think I've posted the url before:

  http://www.st.cs.uni-sb.de/edu/seminare/2005/advanced-fp/docs/sweeny.pdf

It was one of the things that got me interested in Haskell.

> Of course proponents of bondage and discipline languages will argue
> that everything is much easier because we're protected from ourselves.

Rather than "B&D" I prefer to think of it as "let the compiler figure
this out so I don't have to".  It's just like if I have an unbalanced
parenthesis in a C program, I'm better off having it flagged at compile
time than causing a runtime crash.

> Perhaps.  I've been massively impressed by the speed at which GCC is
> adopting fork/join and transactions, and I suspect that it will have
> alot more impact on real-world concurrency.

Maybe so.  It takes a lot more work (or at least a lot more SLOC) to do
something in C than in Haskell, but it could be that the applications
where parallelism has the most impact (like supercomputing, or MapReduce
running across whole data centers) are also the ones that justify the
higher development budgets that it takes to use C.  My hope from Haskell
(maybe not realistic) is to get programmer productivity comparable to
Python with performance comparable to Java and reliability superior to
both.  Low-hassle, safe parallelism from simple constructs is a big win
in that context.  In the most performance critical applications, C and
C++ will probably continue to dominate.

I do think it's awesome that Cilk is now part of GCC, which I only just
found out.

>> It looks like .( does what it's supposed to. 
> Well, yes: the bug is in your program.

Yeah, I hadn't seen .( before, so I tried it and got a surprise.  No big
deal.

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Thread

Comparative Productivity of Programming Languages visualforth@rocketmail.com - 2012-08-21 21:43 -0700
  Re: Comparative Productivity of Programming Languages "A. K." <akk@nospam.org> - 2012-08-22 07:07 +0200
  Re: Comparative Productivity of Programming Languages Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-22 03:35 -0500
    Re: Comparative Productivity of Programming Languages John Passaniti <john.passaniti@gmail.com> - 2012-08-22 14:06 -0700
      Function Points (was: Comparative Productivity of Programming Languages) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-23 14:50 +0000
        Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-23 11:43 -0700
          Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-25 14:13 +0000
            Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 10:12 -0700
              Re: Function Points Doug Hoffman <glidedog@gmail.com> - 2012-08-25 15:39 -0400
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 15:09 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-25 12:34 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 16:43 -0700
                Re: Function Points jacko <jackokring@gmail.com> - 2012-08-25 18:05 -0700
                Re: Function Points jacko <jackokring@gmail.com> - 2012-08-25 20:34 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-26 03:24 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 22:44 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-25 21:19 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 00:36 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-25 21:50 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 01:08 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-26 23:20 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 19:33 -0700
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-27 13:34 -0500
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-27 22:38 +0200
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-28 02:45 -0500
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 18:14 -0700
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 18:24 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-30 14:22 +0000
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-28 03:07 -0500
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-28 08:18 -0700
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-28 12:15 -0500
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-28 23:05 -0700
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-29 03:55 -0500
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-27 22:28 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 20:26 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-28 23:17 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 01:13 -0700
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 02:23 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 02:59 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 22:18 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 20:44 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-31 01:29 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-31 09:33 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 02:58 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 19:39 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-30 14:10 +0000
                Re: Function Points gavino_himself <visploveslisp@gmail.com> - 2012-08-30 20:08 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-30 17:47 -1000
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-27 13:43 -1000
                Re: Function Points "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2012-08-27 12:14 +0100
                Re: Function Points Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-27 05:12 -0700
                Re: Function Points "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2012-08-27 15:52 +0100
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-26 13:09 +0000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 20:52 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-30 14:08 +0000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-30 10:43 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-30 08:25 -1000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 22:42 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-31 01:23 -0400
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-31 03:08 -0500
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-31 18:56 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 02:35 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-31 23:52 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 14:27 +0000
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 14:18 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 17:45 +0200
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 16:14 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 19:13 +0200
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-09-02 03:19 -0500
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:18 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 03:04 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 04:02 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 17:40 +0200
                Re: Function Points jim@rainbarrel.com - 2012-09-02 10:32 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 20:49 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 16:33 -0400
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 17:03 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 09:02 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 16:35 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 13:42 -1000
                Re: Function Points jim@rainbarrel.com - 2012-09-02 16:54 -0700
                Re: Function Points Mark Wills <markrobertwills@yahoo.co.uk> - 2012-09-03 00:29 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 01:30 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 21:21 -1000
                Re: Function Points jim@rainbarrel.com - 2012-09-03 10:37 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-04 07:14 +0000
                Re: Function Points Coos Haak <chforth@hccnet.nl> - 2012-09-03 21:12 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 17:32 -0400
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 17:51 -0400
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-03 22:37 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-04 04:25 -0400
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-04 07:35 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-05 02:13 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-04 20:18 -1000
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-05 10:56 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-05 16:11 -0400
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-05 14:07 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 16:27 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 00:52 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-02 16:28 -0700
                Re: Function Points jim@rainbarrel.com - 2012-09-02 16:48 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 20:21 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 14:45 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 01:12 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 21:26 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 01:06 -0400
                Re: Function Points Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-31 03:29 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-31 10:35 +0000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-31 18:49 -0400
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 14:49 +0000
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-01 08:36 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:11 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 01:58 +0200
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 17:54 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:19 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 03:05 +0200
                Re: Function Points Coos Haak <chforth@hccnet.nl> - 2012-08-31 23:10 +0200
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-31 15:50 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-01 10:31 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 21:52 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:36 -0400
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-01 14:36 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 03:30 +0200
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 23:15 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-02 15:02 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 01:50 +0200
                Re: Function Points jim@rainbarrel.com - 2012-09-02 16:57 -0700
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-03 23:11 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-04 14:30 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-04 10:14 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-04 22:10 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-06 00:19 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-06 17:48 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-06 12:01 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-06 22:02 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-06 14:19 -0700
                Heap (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-07 11:30 +0000
                Re: Heap (was: Function Points) Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-07 18:12 +0200
                Re: Heap (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-07 16:48 +0000
                Re: Heap (was: Function Points) Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-07 21:34 +0200
                Re: Heap Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2012-09-07 22:04 +0100
                Re: Heap anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-08 11:52 +0000
                Re: Heap Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-08 22:48 +0200
                Re: Heap (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-08 12:11 +0000
                priority queue (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-03 11:46 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 15:03 +0200
                Re: Function Points mhx@iae.nl (Marcel Hendrix) - 2012-09-03 22:36 +0200
                Re: Function Points mhx@iae.nl (Marcel Hendrix) - 2012-09-06 20:27 +0200
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-09-02 04:00 -0500
                Re: Function Points visualforth@rocketmail.com - 2012-09-03 10:40 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 20:26 +0200
                Re: Function Points Doug Hoffman <glidedog@gmail.com> - 2012-08-27 11:49 -0400
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 09:16 -0700
                Re: Function Points Josh Grams <josh@qualdan.com> - 2012-08-28 22:46 +0000
                Re: Function Points jacko <jackokring@gmail.com> - 2012-08-28 16:06 -0700
                Re: Function Points Doug Hoffman <glidedog@gmail.com> - 2012-08-28 20:50 -0400
              Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-26 12:59 +0000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 22:24 -0700
        Re: Function Points (was: Comparative Productivity of Programming Languages) John Passaniti <john.passaniti@gmail.com> - 2012-08-23 15:02 -0700
          Re: Function Points (was: Comparative Productivity of Programming Languages) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-25 14:57 +0000
  Re: Comparative Productivity of Programming Languages "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-22 08:07 -0400
    Re: Comparative Productivity of Programming Languages visualforth@rocketmail.com - 2012-08-22 08:12 -0700
  Re: Comparative Productivity of Programming Languages visualforth@rocketmail.com - 2012-08-22 07:37 -0700

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