--- a/Notes.md	Tue Mar 22 14:33:13 2022 +0100
+++ b/Notes.md	Wed Mar 23 13:09:31 2022 +0100
@@ -146,12 +146,52 @@
  - [ ] Is it ok to have "Constructors" for abstract types which create subtypes? For example a Grids() functions that gives different kind of grids based on input?
  - [ ] Figure out how to treat the borrowing parameters of operators. Include in into the struct? Expose via function dispatched on the operator type and grid?
 
+## Identifiers for regions
+The identifiers (`Upper`, `Lower`, `Interior`) used for region indecies should probabily be included in the grid module. This allows new grid types to come with their own regions.
+
 ## Regions and tensormappings
 - [ ] Use a trait to indicate if a LazyTensor uses indices with regions.
     The default should be that they do NOT.
         - [ ] What to name this trait? Can we call it IndexStyle but not export it to avoid conflicts with Base.IndexStyle?
  - [ ] Figure out repeated application of regioned LazyTensors. Maybe an instance of a tensor mapping needs to know the exact size of the range and domain for this to work?
 
+### Ideas for information sharing functions
+```julia
+using StaticArrays
+
+function regions(op::SecondDerivativeVariable)
+    t = ntuple(i->(Interior(),),range_dim(op))
+    return Base.setindex(t, (Lower(), Interior(), Upper()), derivative_direction(op))
+end
+
+function regionsizes(op::SecondDerivativeVariable)
+    sz = tuple.(range_size(op))
+
+    cl = closuresize(op)
+    return Base.setindex(sz, (cl, n-2cl, cl), derivative_direction(op))
+end
+
+
+g = EquidistantGrid((11,9), (0.,0.), (10.,8.)) # h = 1
+c = evalOn(g, (x,y)->x+y)
+
+D₂ᶜ = SecondDerivativeVariable(g, c, interior_stencil, closure_stencils,1)
+@test regions(D₂ᶜ) == (
+    (Lower(), Interior(), Upper()),
+    (Interior(),),
+)
+@test regionsizes(D₂ᶜ) == ((1,9,1),(9,))
+
+
+D₂ᶜ = SecondDerivativeVariable(g, c, interior_stencil, closure_stencils,2)
+@test regions(D₂ᶜ) == (
+    (Interior(),),
+    (Lower(), Interior(), Upper()),
+)
+@test regionsizes(D₂ᶜ) == ((11,),(1,7,1))
+```
+
+
 ## Boundschecking and dimension checking
 Does it make sense to have boundschecking only in getindex methods?
 This would mean no bounds checking in applys, however any indexing that they do would be boundschecked. The only loss would be readability of errors. But users aren't really supposed to call apply directly anyway.

--- a/TODO.md	Tue Mar 22 14:33:13 2022 +0100
+++ b/TODO.md	Wed Mar 23 13:09:31 2022 +0100
@@ -1,14 +1,13 @@
 # TODO
 
-## Skämskudde
- - [ ] Ändra namn på variabler och funktioner så att det följer style-guide
- - [ ] Skriv tester
 
 ## Coding
+ - [ ] Ändra namn på variabler och funktioner så att det följer style-guide
  - [ ] Add new Laplace operator to DiffOps, probably named WaveEqOp(?!!?)
  - [ ] Create a struct that bundles the necessary Tensor operators for solving the wave equation.
  - [ ] Replace getindex hack for flattening tuples with flatten_tuple. (eg. `getindex.(range_size.(L.D2),1)`)
  - [ ] Use `@inferred` in a lot of tests.
+ - [ ] Replace `@inferred` tests with a benchmark suite that automatically tests for regressions.
  - [ ] Make sure we are setting tolerances in tests in a consistent way
  - [ ] Write down some coding guideline or checklist for code conventions. For example i,j,... for indices and I for multi-index
  - [ ] Clean up RegionIndices
@@ -19,12 +18,11 @@
  - [ ] Add possibility to create tensor mapping application with `()`, e.g `D1(v) <=> D1*v`?
  - [ ] Add custom pretty printing to LazyTensors/SbpOperators to enhance readability of e.g error messages.
        See (https://docs.julialang.org/en/v1/manual/types/#man-custom-pretty-printing)
+ - [ ] Samla noggrannhets- och SBP-ness-tester för alla operatorer på ett ställe
  - [ ] Move export statements to top of each module
 
-## Repo
- - [ ] Rename repo to Sbplib.jl
 
-# Wrap up tasks
+ - [ ] Gå igenom alla typ parametrar och kolla om de är motiverade. Både i signaturer och typer, tex D i VariableSecondDerivative. Kan vi använda promote istället?
  - [ ] Kolla att vi har @inbounds och @propagate_inbounds på rätt ställen
  - [ ] Kolla att vi gör boundschecks överallt och att de är markerade med @boundscheck
  - [ ] Kolla att vi har @inline på rätt ställen