September 2nd, 2007, 5:38 pm
QuoteOriginally posted by: CuchulainnQuotePPS : in percentage, how much time do a QF code spend generating RNS? I wonder. [I mean generically, I guess there may be variations.] In cases of interest for me, the speed bottleneck is not in generating rns.If we take a simple 1-factor model and simulate it using Oiler method, then at each step we need to calculate drift, diffusion and an N(0,1) variate. Doing a bit of + and - and then we are done. So, I reckon between 30-40% of effort on the RNG partI see. It's huge, at least compared to my standards.QuoteQuotePPPS : and of course, I use these generators for my own MC codes (integers and reals). At this stage, doing parallel C++ is the way to go I suppose because of all this new processing power. Do you use MPI and/or OpenMP?Actually, I did once coded an MPI version, which is now more or less obsolete because there are libraries doing that ; but for the problems I'm interested in, it happens that this is not necessary because I don't need large scale lattices but a lot of simulations for different parameters. Distributing or parallelizing is no longer of any benefit.