mutating operations are not thread safe. Operations that don't mutate should be thread safe. I can't speak to what Evan said, but I would guess that the way they're using += should be safe.
On Wed, Sep 3, 2014 at 11:58 AM, RJ Nowling <rnowl...@gmail.com> wrote: > David, > > Can you confirm that += is not thread safe but + is? I'm assuming + > allocates a new object for the write, while += doesn't. > > Thanks! > RJ > > > On Wed, Sep 3, 2014 at 2:50 PM, David Hall <d...@cs.berkeley.edu> wrote: > >> In general, in Breeze we allocate separate work arrays for each call to >> lapack, so it should be fine. In general concurrent modification isn't >> thread safe of course, but things that "ought" to be thread safe really >> should be. >> >> >> On Wed, Sep 3, 2014 at 10:41 AM, RJ Nowling <rnowl...@gmail.com> wrote: >> >>> No, it's not in all cases. Since Breeze uses lapack under the hood, >>> changes to memory between different threads is bad. >>> >>> There's actually a potential bug in the KMeans code where it uses += >>> instead of +. >>> >>> >>> On Wed, Sep 3, 2014 at 1:26 PM, Ulanov, Alexander < >>> alexander.ula...@hp.com> >>> wrote: >>> >>> > Hi, >>> > >>> > Is breeze library called thread safe from Spark mllib code in case when >>> > native libs for blas and lapack are used? Might it be an issue when >>> running >>> > Spark locally? >>> > >>> > Best regards, Alexander >>> > --------------------------------------------------------------------- >>> > To unsubscribe, e-mail: dev-unsubscr...@spark.apache.org >>> > For additional commands, e-mail: dev-h...@spark.apache.org >>> > >>> > >>> >>> >>> -- >>> em rnowl...@gmail.com >>> c 954.496.2314 >>> >> >> > > > -- > em rnowl...@gmail.com > c 954.496.2314 >
