How to optimize this short factorial function in scala? (Creating 50000 BigInts)

Question

I\'ve compaired the scala version

(BigInt(1) to BigInt(50000)).reduce(_ * _)

to the python version

reduce(lambda x,y: x*y, rang         


        

Answer 1

Another trick here could be to try both reduceLeft and reduceRight to see what is fastest. On your example I get a much faster execution of reduceRight:

scala> timed { (BigInt(1) to BigInt(50000)).reduceLeft(_ * _) }
Took: 4605 ms

scala> timed { (BigInt(1) to BigInt(50000)).reduceRight(_ * _) }
Took: 2004 ms

Same difference between foldLeft and foldRight. Guess it matters what side of the tree you start reducing from :)