label_fusion_rule to return pair

Author: ogauthe

NDTensors/src/lib/SymmetrySectors/src/abstractsector.jl

@@ -54,8 +54,8 @@ function fusion_rule(c1::AbstractSector, c2::AbstractSector)
 end
 
 function fusion_rule(::NotAbelianStyle, c1::C, c2::C) where {C<:AbstractSector}
-  degen, sectors = label_fusion_rule(C, sector_label(c1), sector_label(c2))
-  return gradedrange(labelled.(degen, sectors))
+  sector_degen_pairs = label_fusion_rule(C, sector_label(c1), sector_label(c2))
+  return gradedrange(sector_degen_pairs)
 end
 
 # abelian case: return Sector
@@ -64,7 +64,7 @@ function fusion_rule(::AbelianStyle, c1::C, c2::C) where {C<:AbstractSector}
 end
 
 function label_fusion_rule(sector_type::Type{<:AbstractSector}, l1, l2)
-  return [1], [abelian_label_fusion_rule(sector_type, l1, l2)]
+  return [abelian_label_fusion_rule(sector_type, l1, l2) => 1]
 end
 
 # ================================  GradedAxes interface  ==================================

NDTensors/src/lib/SymmetrySectors/src/sector_definitions/fib.jl

@@ -31,9 +31,11 @@ quantum_dimension(::NotAbelianStyle, f::Fib) = istrivial(f) ? 1.0 : ((1 + √5)
 
 # Fusion rules identical to su2₃
 function label_fusion_rule(::Type{Fib}, l1, l2)
-  degen, suk_sectors = label_fusion_rule(su2{3}, l1, l2)
+  suk_sectors_degen = label_fusion_rule(su2{3}, l1, l2)
+  suk_sectors = first.(suk_sectors_degen)
+  degen = last.(suk_sectors_degen)
   sectors = Fib.(sector_label.(suk_sectors))
-  return degen, sectors
+  return sectors .=> degen
 end
 
 label_to_str(f::Fib) = istrivial(f) ? "1" : "τ"

NDTensors/src/lib/SymmetrySectors/src/sector_definitions/ising.jl

@@ -31,9 +31,11 @@ quantum_dimension(::NotAbelianStyle, i::Ising) = (sector_label(i) == 1//2) ? √
 
 # Fusion rules identical to su2₂
 function label_fusion_rule(::Type{Ising}, l1, l2)
-  degen, suk_sectors = label_fusion_rule(su2{2}, l1, l2)
+  suk_sectors_degen = label_fusion_rule(su2{2}, l1, l2)
+  suk_sectors = first.(suk_sectors_degen)
+  degen = last.(suk_sectors_degen)
   sectors = Ising.(sector_label.(suk_sectors))
-  return degen, sectors
+  return sectors .=> degen
 end
 
 # TODO: Use `Val` dispatch here?

NDTensors/src/lib/SymmetrySectors/src/sector_definitions/o2.jl

@@ -71,5 +71,5 @@ function label_fusion_rule(::Type{O2}, l1, l2)
       end
     end
   end
-  return degens, O2.(labels)
+  return O2.(labels) .=> degens
 end

NDTensors/src/lib/SymmetrySectors/src/sector_definitions/su.jl

@@ -94,7 +94,7 @@ GradedAxes.dual(s::SU{2}) = s
 function label_fusion_rule(::Type{<:SU{2}}, s1, s2)
   irreps = [SU{2}((i,)) for i in (abs(s1[1] - s2[1])):2:(s1[1] + s2[1])]
   degen = ones(Int, length(irreps))
-  return degen, irreps
+  return irreps .=> degen
 end
 
 # define angular momentum-like interface using half-integers
@@ -123,7 +123,7 @@ function label_fusion_rule(::Type{<:SU{3}}, left, right)
   end
 
   if right[1] == 0  # avoid issues with singlet
-    return [1], [SU{3}(left)]
+    return [SU{3}(left) => 1]
   end
 
   left_row1 = left[1]
@@ -173,5 +173,6 @@ function label_fusion_rule(::Type{<:SU{3}}, left, right)
   unique_labels = sort(unique(irreps))
   degen = [count(==(irr), irreps) for irr in unique_labels]
   sectors = SU{3}.(unique_labels)
-  return degen, sectors
+  @show sectors, degen
+  return sectors .=> degen
 end

NDTensors/src/lib/SymmetrySectors/src/sector_definitions/su2k.jl

@@ -23,5 +23,5 @@ function label_fusion_rule(::Type{su2{k}}, j1, j2) where {k}
   labels = collect(abs(j1 - j2):min(k - j1 - j2, j1 + j2))
   degen = ones(Int, length(labels))
   sectors = su2{k}.(labels)
-  return degen, sectors
+  return sectors .=> degen
 end