Unless the vectors in question are small, the allocation of a one-element array is unlikely to be significant. If the vectors are small, writing out the dot product yourself is likely to be faster; In fact, it may be faster anyway.
> On Jan 2, 2014, at 7:38 AM, Ivar Nesje <[email protected]> wrote: > > Thanks for correcting me. I should have checked better before answering, > especially because it is so simple in Julia to follow the functions and see > what actually gets calculated. > > kl. 13:29:49 UTC+1 torsdag 2. januar 2014 skrev Andreas Noack Jensen følgende: >> >> The problem here is that the method in operators.jl is >> At_mul_B(a,b)=transport(a)*b and therefore there is a transposed copy in the >> calculation. >> >> >> 2014/1/2 Ivar Nesje <[email protected]> >>> Julia does part of transformation automatically for you. >>> >>> If you look at >>> >>> julia> @which a.'*b >>> At_mul_B(a,b) at operators.jl:122 >>> >>> You can see that the call is automatically rewritten to At_mul_B(a,b) >>> without making a transposed copy. >>> >>> I am not sure what you can do about the result being a 1 element >>> Array{Complex{Float64},1} instead of just a Complex{Float64}. >>> >>> Ivar >>> >>> kl. 13:02:39 UTC+1 torsdag 2. januar 2014 skrev Sheehan Olver følgende: >>>> >>>> I want to do >>>> >>>> a.'*b >>>> >>>> where a and b are Vector{Complex}, but this returns an Array, not a >>>> constant, and probably does unneccesary memory allocation for when >>>> constructing a.' >>>> >>>> If it was >>>> >>>> a'*b >>>> >>>> I can just replace it with dot(a,b). Is there an equivalent that doesn't >>>> conjugate the first argument? >> >> >> >> -- >> Med venlig hilsen >> >> Andreas Noack Jensen
