However, as C was one of the faster, I'll use it as a comparison.
fib.c, compiled with 03: 10.49user 0.28system 0:11.62elapsed
#include <stdio.h>
long fib(long n) {
if (n <= 1) return 1;
return fib(n - 1) + fib(n - 2);
}
int main(void) {
printf("%li\n", fib(46));
return 0;
}
function fib(n)
if n <= 1 then
return 1
else
return fib(n - 1) + fib(n - 2)
end
end
print(fib(46))
Lua 5.3: 717.21user 8.40system 14:19.47elapsed
As Luajit was so much slower than C for this, which can be somewhat surprising.
Luajit would probably beat Ruby, for it's interpreted crown, but without optimisation, it won't beat the big boys.
I would say, that Lua isn't a good fit for solving this kind of problem, with these constraints, because every function call requires a hash lookup, which is irritating.
Of course, you could use Luajit's FFI to use C's implementation, which would be somewhat faster. Or expose the C implementation as a Lua library.
However, Lua is probably also a really good fit for memoization, and other techniques like that.
local nums = {}
local fib
fib = function(n)
if n <= 1 then
return 1
else
if nums[n] then
return nums[n]
else
nums[n] = fib(n - 1) + fib(n - 2)
return nums[n]
end
end
end
print(fib(46))