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From: nowias00@marvin.informatik.uni-dortmund.de (Mark Nowiasz)
Newsgroups: comp.lang.beta
Subject: Re: BETA questions
Date: 24 Apr 1995 08:44:58 GMT
Organization: CS Department, University of Dortmund, Germany
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References: <3jq90s$ojp@belfort.daimi.aau.dk> <3n5eht$m2i@fbi-news.informatik.uni-dortmund.de> <agesen.798402297@Xenon.Stanford.EDU>
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Ole Agesen (agesen@Xenon.Stanford.EDU) wrote:
: nowias00@marvin.informatik.uni-dortmund.de (Mark Nowiasz) writes:


: Mark, I would be interested in seeing both of your programs.
: Any chance they are small enough that you can post them?

Sure, here they are..

First the BETA-Pattern :

ORIGIN '~beta/basiclib/current/betaenv'
-- program: descriptor --


(#
   p_rekursive : (#
                   return, m : @integer
                   enter m
                   do
                      (if m > 2
                          // true then ((m - 1 -> p_rekursive) 
                                       + (m - 2 -> p_rekursive)) -> return
                          // false then 1 -> return;
                      if)
                      exit return
                #);

   p_iterative : (#
                   return : @integer;
                   repetition   : [1]@integer
                   enter repetition.new
                   do
                      (if repetition.range > 2
                          // true then 1 -> repetition[1] -> repetition[2];
                             (for i : repetition.range - 2 repeat
                                repetition[i] + repetition[i+1] -> repetition[i + 2]
                             for);
                             repetition[repetition.range] -> return;
                         // false then 1 -> return;
                      if)
                      exit return
                  #);

   value : @ integer;                  
   do
      'Value : ' -> PutText;
      GetInt -> Abs -> value -> p_iterative -> PutInt;
      NewLine; 
      value -> p_recursive -> PutInt;
      NewLine;

#)

Now the C++ - program :

#include <iostream.h>

unsigned int f_recursive(unsigned m)
{
	if (m > 2)
		return f_recursive(m - 1) + f_recursive(m - 2);
	else return 1;
};

unsigned int f_iterative(unsigned m)
{
	unsigned ret = 1;
	unsigned *vector = new unsigned [m];
	if (vector && (m > 2))
	{
		vector[0] = vector[1] = 1;
		for (unsigned i = 2; i < m; i++)
			vector[i] = vector[i-1] + vector[i-2];
		ret = vector[m - 1];
		delete [] vector;
	};
	return ret;
};

int main(int argc, char *argv[])
{
	unsigned value;
	
	cout << "Enter Value:";
	cin >> value;
	cout << f_recursive(value) << endl << f_iterative(value) << endl;
};

The recursive versions are the ones which I've compared, because the run-time
of the iterative ones are nearly not measurable. ( << 1 second).

: Another question: did you compare CPU time or real time of the two 
: programs? The former increases linearly with the work load, so it
: may not be a good measure (unless you only run that one program).

When I was running the BETA-Pattern, I was the only one working on the SUN-4.
There were certain X-Processes running (like clock) but with nice-levels
increased. (The average load was << 0.5).

Like Unix and OS/2 the multitasking of the amiga is preemptive, but since I
was the only user and there was no other task running (except, of course, the
usual system-tasks and a clock program), so the loads of the two computer
systems are neglectible.


--
        Mark

===============================================================
Mark Nowiasz         nowias00@marvin.informatik.uni-dortmund.de
Kronenstrasse 3
44625 Herne
Germany

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