No, if you know the size to begin with, better to allocate to that size and use a standard for loop to set up the values.
--Tim On Saturday, November 28, 2015 12:17:03 AM Christoph Ortner wrote: > Is this essentially as efficient as preallocating the correct size to begin > with? > Christoph > > On Wednesday, 25 November 2015 16:48:16 UTC, Tim Holy wrote: > > I = Int[] > > J = Int[] > > V = Float64[] > > > > while have_more_entries_to_add() > > > > i, j, v = get_next_entry() > > > > push!(I, i); push!(J, j); push!(V, v) > > > > end > > > > arry = sparse(I, J, V) > > > > --Tim > > > > On Wednesday, November 25, 2015 08:05:12 AM Cedric St-Jean wrote: > > > How do people usually do this? Assignment is slow > > > > > > arr = spzeros(1000,1000) > > > for ... > > > > > > arr[i,j] = ... > > > > > > ... > > > > > > and indeed, in scipy one would use a non-CSC format for construction, > > > > then > > > > > convert it to CSC. I've seen some comments that one should just build > > > > the > > > > > SparseMatrixCSC object directly for performance. Is that still the usual > > > advice? > > > > > > Cédric
