I just put all your top-level statements (except for the two helper functions) into a function of its own:
julia> @time main() elapsed time: 0.162065867 seconds (14434040 bytes allocated) 4179871 I don't think my 5 year old laptop could be *that* much faster than your computer. Take a look at the performance tips section for more advice along these lines: http://docs.julialang.org/en/latest/manual/performance-tips/ On Tuesday, July 22, 2014 6:13:40 PM UTC-4, Patrick O'Leary wrote: > > I suspect you might find the profiler helpful: > http://julia.readthedocs.org/en/latest/stdlib/profile/ > > (And the ProfileView.jl package provides a nice visualization of profiler > results--you should check it out too!) > > On Tuesday, July 22, 2014 4:47:09 PM UTC-5, Arnaud Amiel wrote: >> >> To learn how to use Julia, I am running through the project Euler >> problems (I had already solved most of them using other languages) and up >> to now, they have all comfortably been solved under 1s without any clever >> algorithm, even sometimes purposely brute forced. >> >> However I am stuck on problem 23 (Find the sum of all the positive >> integers which cannot be written as the sum of two abundant numbers.) which >> solves in 8 s. The surprising thing to me is that what I assume to be the >> hard part is solved in 0.1 s. >> >> I have been struggling on and off for the last week but have gone >> nowhere. I thought a fresh pair of eyes may see something. >> >> Here is my code: >> >> const maxAbundant = 28123 >> >> function sumOfDivisors(n::Int) >> f = factor(n) >> counter = 1 >> for i in keys(f) >> count = 1 >> for j in 1:f[i] >> count += i^j >> end >> counter *= count >> end >> counter-n >> end >> >> function isAbundant(n::Int) >> sumOfDivisors(n) > n ? true : false >> end >> >> abundantNumbers=Array(Int,1) >> >> abundantNumbers[1]=12 >> sizehint(abundantNumbers, maxAbundant) >> >> for i = 13:maxAbundant >> if isAbundant(i) >> push!(abundantNumbers, i) >> end >> end >> >> isSumOfAbundant=falses(1,maxAbundant) >> >> tic() >> for i = 1:length(abundantNumbers) >> for j = i:length(abundantNumbers) >> SumOfAbundant = abundantNumbers[i] + abundantNumbers[j] >> if SumOfAbundant <= maxAbundant >> isSumOfAbundant[SumOfAbundant]=true >> else >> break >> end >> end >> end >> toc() >> >> >> result=0 >> for i = 1:maxAbundant >> if !isSumOfAbundant[i] >> result += i >> end >> end >> >> result >> >> When run with @time I get: >> elapsed time: 7.967364175 seconds >> elapsed time: 8.06121492 seconds (1359946448 bytes allocated, 18.32% gc >> time) >> >> So I am convinced the bit between tic() and toc() is not right and gc >> time may be a clue but I really can't find why. >> >> Any help will be greatly appreciated. >> >> One thing I find annoying with Julia is that sometimes what seems to me a >> very insignificant change in the code has dramatic effect in the execution >> time. It is anyway a great tool to try things and find solutions quickly. I >> wish I had had Julia when I started on Project Euler. >> >> Thanks, >> >> Arnaud >> >
