for a rather large sparse matrix, and spy just hangs there for too long for it to be useful to me… MATLAB’s spy is quite fast in comparison. I’m guessing Julia’s spy plot is not binning the data? But how can I get that info since I can’t find the documentation:

help?> spy
search: spy spy! speye display Display displaysize displayable redisplay popdisplay isempty TextDisplay supertype pushdisplay
No documentation found.
Plots.spy is a Function.
# 1 method for generic function "spy":
spy(args...; kw...) in Plots at /Users/XXXXXX/.julia/v0.6/RecipesBase/src/RecipesBase.jl:367

It is that slow that I don’t know how long it is gonna take because I cannot afford to wait… In MATLAB, spy is a convenient way to check a sparsity pattern, and takes almost no time to plot. It seems to me spy should never be slow, right?

Plots.jl has a slow first plot time because that’s when it sets up the backend and this is orthogonal to spy. You still haven’t mentioned whether it’s just the first plot time or not.

It also depends on the backend you are using, Gadlfy’s spy is very slow for example. Maybe try GR. Sometimes I just write a png, which is often faster that plotting.

Hmmm… this is more like a workaround. I have been using spy for UnicodePlots hoping that the spy from Plots would get fixed, but it still seems to be incredibly slow.