On Wed, Oct 15, 2014 at 11:43 AM, Jiahao Chen <[email protected]> wrote: >> We can safely assume that axpy is vectorized > > I think it would depend on how closely the BLAS implementations follow the > letter of the law when it comes to floating-point semantics. Arch Robison > has written and spoken (recently at JuliaCon, but also elsewhere) about how > the nonassociativity of floating point operations means that computations > that require reordering of operations to vectorize cannot be vectorized > without compromising strict IEEE-754-compliant rounding behavior.
axpy is not affected by this, it has sufficiently many independent floating point operations. -erik -- Erik Schnetter <[email protected]> http://www.perimeterinstitute.ca/personal/eschnetter/
