some bigfloats tests

sandbox/test_getetdcoeffsBigFloat.jl

@@ -3,14 +3,14 @@ using FourierFlows
 n, L = 128, 2π
 g = TwoDGrid(n, L)
 ν = 1e-3
-LC = -ν*g.KKrsq.^2  + im*g.Kr
-LC[1, 1]=0
-dt = 0.1
+LC = -ν*g.KKrsq  + im*g.Kr
+# LC = -ν*g.KKrsq.^8  + im*g.Kr
+dt = 0.001
 
 
 
 
-function getetdcoeffs(dt, LC; ncirc=32, rcirc=eltype(LC)(14))
+function getetdcoeffs(dt, LC; ncirc=32, rcirc=eltype(LC)(1))
 
   shape = Tuple(cat(1, ncirc, ones(Int, ndims(LC))))
 
@@ -50,36 +50,35 @@ function getetdcoeffsBigFloat(dt, LC)
   expL2 = big.(exp.(L/2))
   L = big.(L)
 
-  ζc = @. Complex{Float64}( ( expL2-1 ) / L )
-  αc = @. Complex{Float64}( (-4 - L + expL*(4-3L + L^2))/L^3 )
-  βc = @. Complex{Float64}( ( 2 + L + expL*(-2 + L))/L^3 )
-  Γc = @. Complex{Float64}( (-4 - 3L -L^2 + expL*(4 - L))/L^3 )
-
-
   if eltype(LC) <: Real
-    ζ = dt*real.(ζc)
-    α = dt*real.(αc)
-    β = dt*real.(βc)
-    Γ = dt*real.(Γc)
+    ζ = @. dt*Float64( ( expL2-1 ) / L )
+    α = @. dt*Float64( (-4 - L + expL*(4-3L + L^2))/L^3 )
+    β = @. dt*Float64( ( 2 + L + expL*(-2 + L))/L^3 )
+    Γ = @. dt*Float64( (-4 - 3L -L^2 + expL*(4 - L))/L^3 )
   else
-    ζ = dt*ζc
-    α = dt*αc
-    β = dt*βc
-    Γ = dt*Γc
+    ζ = @. dt*Complex{Float64}( ( expL2-1 ) / L )
+    α = @. dt*Complex{Float64}( (-4 - L + expL*(4-3L + L^2))/L^3 )
+    β = @. dt*Complex{Float64}( ( 2 + L + expL*(-2 + L))/L^3 )
+    Γ = @. dt*Complex{Float64}( (-4 - 3L -L^2 + expL*(4 - L))/L^3 )
   end
 
+  if isnan(ζ[1, 1]); ζ[1, 1] = dt/2; end
+  if isnan(α[1, 1]); α[1, 1] = dt/6; end
+  if isnan(β[1, 1]); β[1, 1] = dt/6; end
+  if isnan(Γ[1, 1]); Γ[1, 1] = dt/6; end
+
   ζ, α, β, Γ
 end
 
 
 
-@time ζ1, α1, β1, Γ1 = getetdcoeffs(dt, LC, ncirc=32)
-ζ1[1, 1], α1[1, 1], β1[1, 1], Γ1[1, 1] = 0, 0, 0, 0
+@time ζ1, α1, β1, Γ1 = getetdcoeffs(dt, LC, ncirc=32, rcirc=100)
+# ζ1[1, 1], α1[1, 1], β1[1, 1], Γ1[1, 1] = 0, 0, 0, 0
 @time ζ2, α2, β2, Γ2 = getetdcoeffsBigFloat(dt, LC)
-ζ2[1, 1], α2[1, 1], β2[1, 1], Γ2[1, 1] = 0, 0, 0, 0
+# ζ2[1, 1], α2[1, 1], β2[1, 1], Γ2[1, 1] = 0, 0, 0, 0
 
 
-println("diff error ζ: ", norm(ζ1-ζ2, Inf))
-println("diff error α: ", norm(α1-α2, Inf))
-println("diff error β: ", norm(β1-β2, Inf))
-println("diff error Γ: ", norm(Γ1-Γ2, Inf))
+println("diff error ζ: ", norm(ζ1-ζ2, Inf)/norm(ζ1, Inf))
+println("diff error α: ", norm(α1-α2, Inf)/norm(α1, Inf))
+println("diff error β: ", norm(β1-β2, Inf)/norm(β1, Inf))
+println("diff error Γ: ", norm(Γ1-Γ2, Inf)/norm(Γ1, Inf))