I’m not really sure. My not totally informed sense is that this is likely to be generally slow since you have to check the type every time to determine what the inner field means.
But someone with more knowledge of Julia internals would need to confirm that. — John On Jan 6, 2014, at 10:34 AM, Brendan O'Connor <[email protected]> wrote: > On Sunday, January 5, 2014 8:54:08 PM UTC-5, John Myles White wrote: > Looking at this now, what are the types of the variables on the bolded lines? > If they’re specific real-valued types, I’m surprised they’re so slow. > > They're all Float64, or at least, they should be. code_typed() says they are: > > w0 = > /(-(+(getindex(top(getfield)(n0,:counts),wordID::Int64),top(box)(Float64,top(div_float)(betaHere::Float64,top(box)($(Float64),top(sitofp)($(Float64),V::Int64))::Float64))::Float64),on0::Int64),-(+(top(getfield)(top(getfield)(n0,:counts),:total),betaHere::Float64),top(box)($(Int64),top(zext_int)($(Int64),on_cur::Bool))::Int64)) > # line 338: > w1 = > /(-(+(getindex(top(getfield)(n1,:counts),wordID::Int64),top(box)(Float64,top(div_float)(betaHere::Float64,top(box)($(Float64),top(sitofp)($(Float64),V::Int64))::Float64))::Float64),on1::Int64),-(+(top(getfield)(top(getfield)(n1,:counts),:total),betaHere::Float64),top(box)($(Int64),top(zext_int)($(Int64),on_cur::Bool))::Int64)) > # line 339: > p0 = > -(+(top(getfield)(top(getfield)(cur_docnode,:left),:count),top(box)(Float64,top(div_float)(top(getfield)(mm::TreeTM,:gammaConc)::Float64,top(box)($(Float64),top(sitofp)($(Float64),2))::Float64))::Float64),on0::Int64) > # line 340: > p1 = > -(+(top(getfield)(top(getfield)(cur_docnode,:right),:count),top(box)(Float64,top(div_float)(top(getfield)(mm::TreeTM,:gammaConc)::Float64,top(box)($(Float64),top(sitofp)($(Float64),2))::Float64))::Float64),on1::Int64) > # line 341: > q = /(*(p1,w1),+(*(p1,w1),*(p0,w0))) # line 343: > > > Right now it’s not possible to have an abstract type with fields, so field > lookup should be pretty consistently fast. > > What I meant was: > > abstract A > type B <: A > x > end > type C<: A > y > end > > ... and you have a datastructure typed A, but actually contains a mix of B's > and C's. You have code that knows it's always accessing type B, and accesses > the "x" field. > Under what circumstances is this fast? > > -Brendan > > > >
