Add TODO for using planar rules in rrules [skip ci]

Jutho · Jun 3, 2024 · 39942c1 · 39942c1
1 parent 73992c9
commit 39942c1
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/ext/TensorKitChainRulesCoreExt.jl b/ext/TensorKitChainRulesCoreExt.jl
@@ -114,6 +114,8 @@ function ChainRulesCore.rrule(::typeof(⊗), A::AbstractTensorMap, B::AbstractTe
  projectA = ProjectTo(A)
  projectB = ProjectTo(B)
  function otimes_pullback(ΔC_)
+ # TODO: this rule is probably better written in terms of inner products,
+ # using planarcontract and adjoint tensormaps would remove the twists.
  ΔC = unthunk(ΔC_)
  pΔC = ((codomainind(A)..., (domainind(A) .+ numout(B))...),
  ((codomainind(B) .+ numout(A))...,