Fix undefined tol and remove unused variable in QR and LQ pullback (#…

…127)

* Fix undefined `tol` and remove unused variable in QR and LQ pullback

* Avoid closure problem

ext/TensorKitChainRulesCoreExt.jl

@@ -536,9 +536,8 @@ function qr_pullback!(ΔA::AbstractMatrix, Q::AbstractMatrix, R::AbstractMatrix,
                       atol::Real=0,
                       rtol::Real=atol > 0 ? 0 : eps(real(eltype(R)))^(3 / 4))
     Rd = view(R, diagind(R))
-    p = let tol = atol > 0 ? atol : rtol * maximum(abs, Rd)
-        findlast(x -> abs(x) >= tol, Rd)
-    end
+    tol = atol > 0 ? atol : rtol * maximum(abs, Rd)
+    p = findlast(>=(tol) ∘ abs, Rd)
     m, n = size(R)
 
     Q1 = view(Q, :, 1:p)
@@ -548,7 +547,6 @@ function qr_pullback!(ΔA::AbstractMatrix, Q::AbstractMatrix, R::AbstractMatrix,
     ΔA1 = view(ΔA, :, 1:p)
     ΔQ1 = view(ΔQ, :, 1:p)
     ΔR1 = view(ΔR, 1:p, :)
-    ΔR11 = view(ΔR, 1:p, 1:p)
 
     M = similar(R, (p, p))
     ΔR isa AbstractZero || mul!(M, ΔR1, R1')
@@ -591,9 +589,8 @@ function lq_pullback!(ΔA::AbstractMatrix, L::AbstractMatrix, Q::AbstractMatrix,
                       atol::Real=0,
                       rtol::Real=atol > 0 ? 0 : eps(real(eltype(L)))^(3 / 4))
     Ld = view(L, diagind(L))
-    p = let tol = atol > 0 ? atol : rtol * maximum(abs, Ld)
-        findlast(x -> abs(x) >= tol, Ld)
-    end
+    tol = atol > 0 ? atol : rtol * maximum(abs, Ld)
+    p = findlast(>=(tol) ∘ abs, Ld)
     m, n = size(L)
 
     L1 = view(L, :, 1:p)
@@ -603,7 +600,6 @@ function lq_pullback!(ΔA::AbstractMatrix, L::AbstractMatrix, Q::AbstractMatrix,
     ΔA1 = view(ΔA, 1:p, :)
     ΔQ1 = view(ΔQ, 1:p, :)
     ΔL1 = view(ΔL, :, 1:p)
-    ΔR11 = view(ΔL, 1:p, 1:p)
 
     M = similar(L, (p, p))
     ΔL isa AbstractZero || mul!(M, L1', ΔL1)