So you can't have a (pseudo) random number generator?

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Post #247,575 by Another Scott 3/11/06 1:24:33 PM Reply	So you can't have a (pseudo) random number generator?
Post #247,576 by admin 3/11/06 1:34:03 PM Reply	Those don't have side-effects And given the same seed, a pseudo-random number generator will always return the same sequence of "random" numbers. Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..."
Post #247,577 by Another Scott 3/11/06 1:52:48 PM Reply	I was too tearse. Some random number generators are more random than others. :-) I'm aware of the limitations of typical pseudo random number generators. I was too tearse in putting that in the Subject. (One of many true random number generators is [link\|http://www.fourmilab.ch/hotbits/\|HotBits].) I wasn't questioning the "side-effects" aspect (I don't think), I was wondering whether it would be possible to hypotheically code a random number generator in a pure functional language given that, apparently, f(x0,t) = y0 for all x0 for a fuctional language, where a random number generator would give f(x0,t) = y(x0,t,gamma) (where gamma is some truly radom parameter). (If I didn't mess the notation up.) Presumably the code would talk to a radioactivity sensor or something similar that was truly random. I would think that it must be possible, but wonder how it would be simply explained and whether it violates the premise of functional programming. Thanks. Cheers, Scott.
Post #247,578 by admin 3/11/06 2:00:46 PM 3/11/06 2:02:24 PM Reply	For pure functional programming, no Because the program won't be provable for a given set of inputs. Unless you count the external random number as one of the inputs, I suppose. Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..." Edited by admin March 11, 2006, 02:02:24 PM EST Expand All History
Post #247,587 by ChrisR 3/11/06 4:01:46 PM Reply	You can if you thread the state through the functions... ...and hence the introduction of monads.

Erlang? - (tuberculosis) - (22) - Aug. 21, 2007, 06:24:22 AM EDT

Threads, Messages, and Pattern Matching.... - (ChrisR) - (21) - March 10, 2006, 08:50:15 AM EST

Right so to me this sounds like the ultimate SOA language - (tuberculosis) - (20) - Aug. 21, 2007, 06:27:15 AM EDT

I dunno - (jake123) - (18) - March 11, 2006, 03:19:13 AM EST

Quick CS101 pointer? Diff between fucntional and imperative? -NT - (drewk) - (17) - March 11, 2006, 08:33:22 AM EST

Re: Quick CS101 pointer? Diff between fucntional and imperat - (admin) - (16) - March 11, 2006, 09:45:04 AM EST

Okay, remember hearing that before, and I understand ... - (drewk) - (6) - March 11, 2006, 10:01:55 AM EST

Re: Okay, remember hearing that before, and I understand ... - (admin) - (5) - March 11, 2006, 01:19:24 PM EST

So you can't have a (pseudo) random number generator? -NT - (Another Scott) - (4) - March 11, 2006, 01:24:33 PM EST

Those don't have side-effects - (admin) - (3) - March 11, 2006, 01:34:03 PM EST

I was too tearse. - (Another Scott) - (2) - March 11, 2006, 01:52:48 PM EST

For pure functional programming, no - (admin) - March 11, 2006, 02:02:24 PM EST

You can if you thread the state through the functions... - (ChrisR) - March 11, 2006, 04:01:46 PM EST

Is this worth going through? - (broomberg) - (3) - March 11, 2006, 10:16:20 AM EST

Shorter read.... - (ChrisR) - (2) - March 11, 2006, 10:42:19 AM EST

Already did that - (broomberg) - (1) - March 11, 2006, 11:22:16 AM EST

I didn't find the gentle intro useful when I read it... - (ChrisR) - March 11, 2006, 05:16:48 PM EST

The three pillars - (ChrisR) - (4) - March 11, 2006, 10:56:30 AM EST

You just lost me - (drewk) - (3) - March 11, 2006, 12:17:52 PM EST

Google the terms - (ben_tilly) - March 11, 2006, 04:17:40 PM EST

Quick explanation - (ChrisR) - (1) - March 11, 2006, 04:46:51 PM EST

One other important concept worth mentioning is Currying - (ChrisR) - March 11, 2006, 05:06:03 PM EST

Erlang does look very intriguing, will hopefully influence - (tonytib) - March 11, 2006, 02:15:26 PM EST

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