The reason rowvals exists is to access the vector of row-indices of a CSC-matrix, i.e. one of the internals of CSC, to allow efficient iteration over the non-zeros. However, there is no equivalent colvals internal, so there is little reason to do this and even less reason to encourage it. Consider:
julia> s = sprand(10^7, 10^7, 1e-7); julia> @time rowvals(s); 0.000004 seconds (4 allocations: 160 bytes) julia> @time colvals(s); 0.508060 seconds (20 allocations: 533.748 MB, 14.61% gc time) On Fri, 2016-04-01 at 10:48, Anonymous <espr...@gmail.com> wrote: > There is a rowals function, and then there is a find function, and the find > function actually allows you to write a one line colvals function: > > colvals(S::SparseMatrixCSC) = round(Int, floor(find(S)/(size(S, 1)+0.1))+1) > > shouldn't someone add this to base?
