Thanks, I guess the number of threads depends many things then. Carlos
On Thursday, March 27, 2014 10:08:04 PM UTC+1, Tim Holy wrote: > > For such operations, Julia calls out to OpenBLAS; while OpenBLAS is > terrific, > the number of threads has been a bit of a sore point. > > https://github.com/xianyi/OpenBLAS/issues/103 > > --Tim > > On Thursday, March 27, 2014 12:15:04 PM Carlos Stein wrote: > > Hi all, > > > > I'm getting started with Julia, looks great. > > > > I was testing the performance for a simple array product *(A*v)* and it > > depended if *v* is a vector or an array. The matrix version > > > > A = randn(400,4000) > > > > v = randn(4000,1) > > y = A*v > > > > > > used one core, while the vector version > > > > > > A = randn(400,4000) > > > > v = randn(4000) > > y = A*v > > > > > > used all 16 cores and was 10x faster. > > > > Is there an easy way to know and choose how many cores will be used for > a > > given operation? > > > > Thanks! Carlos >
