allow range in makefilter

docs/src/timestepping.md

@@ -51,12 +51,12 @@ set_theme!(Theme(linewidth = 3, fontsize = 20))
 ```@example 1
 using FourierFlows, CairoMakie
 
-K = range(0, stop=1, length=100) # non-dimensional wavenumber k * dx / π
+K = 0:0.01:1 # non-dimensional wavenumber k * dx / π
 
-filter = FourierFlows.makefilter(collect(K))
+filter = FourierFlows.makefilter(K)
 
 fig = Figure()
-ax = Axis(fig[1, 1], xlabel = "k dx / π", ylabel = "filter")
+ax = Axis(fig[1, 1], xlabel = "k dx / π", ylabel = "filter", aspect=2.5, xticks=0:0.2:1)
 
 lines!(ax, K, filter)
 

src/domains.jl

@@ -502,16 +502,15 @@ outer wavenumber `outerK` is `tol`, where `tol` is a small number, close to mach
 decay = - log(tol) / (outerK - innerK)^order
 ```
 """
-function makefilter(K::Array; order=4, innerK=2/3, outerK=1, tol=1e-15)
-  TK = typeof(K)
+function makefilter(K; order=4, innerK=2/3, outerK=1, tol=1e-15)
   K = Array(K)
 
-  decay = -log(tol) / (outerK - innerK)^order # decay rate for filtering function
+  decay = -log(tol) / (outerK - innerK)^order
 
   filter = @. exp(- decay * (K - innerK)^order)
   filter[K .< innerK] .= 1
 
-  return TK(filter)
+  return filter
 end
 
 function makefilter(g::OneDGrid; realvars=true, kwargs...)