If you expect that you're going to have to push a lot of values onto a vector, you can avoid the cost of incremental reallocation by doing it once up front.
On Wednesday, October 21, 2015, Jacob Quinn <quinn.jac...@gmail.com> wrote: > The way I came to understand was to just take a peak at the [source code]( > https://github.com/JuliaLang/julia/blob/ae154d076a6ae75bfdb9a0a377a6a5f9b0e1096f/src/array.c#L670); > I find it pretty legible. The basic idea is that the underlying "storage" > of a Julia Array{T,N} can actually be (and often is) different than the > size(A) in Julia. sizehint! modifies that underlying storage without > changing the size(A) in Julia. > > -Jacob > > On Wed, Oct 21, 2015 at 12:46 PM, Seth <catch...@bromberger.com > <javascript:_e(%7B%7D,'cvml','catch...@bromberger.com');>> wrote: > >> I know it's good to use sizehint! with an estimate of the sizes of >> (variable-length) containers such as vectors, but I have a couple of >> questions I'm hoping someone could answer: >> >> 1) what are the benefits of using sizehint!? (How does it work, and under >> what circumstances is it beneficial?) >> 2) what are the implications (positive/negative, if any) of >> overestimating the size of a container? >> >> Thanks. >> > >
