I'm new to Ruby BECAUSE of MacRuby
While learning I run this simple exercise (the sum of even fibonacci less than
4 million) on both MacRuby 0.5.2 and ruby 1.9.1.
the recursive version runs about 5 times faster on MacRuby and that was
expected but the iterative runs about 1000!!! times slower, and that is
*frankly* unacceptable.
What's going on?
uliano
def fib_rec(n)
n < 2 ? n : fib_rec(n-1) + fib_rec(n-2)
end
def fib_iter(limit)
yield 0
yield 1
lastbut=0
last=1
while true
a=lastbut+last
if a<=limit
yield a
else
return
end
lastbut=last
last=a
end
end
sum=0
i=0
start=Time.now
while (f=fib_rec(i))<=4_000_000
sum += f if f%2==0
i+=1
end
time=Time.now-start
puts 'recursive'
puts 'sum = ',sum
puts 'time = ',time
sum=0
start=Time.now
fib_iter(4_000_000) { |f| sum+=f if f%2==0}
time=Time.now-start
puts 'iterative'
puts 'sum = ',sum
puts 'time = ',time
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