allow nested broadcast

Author: ogauthe

src/blockedtuple.jl

@@ -72,6 +72,8 @@ function Base.copy(
   return widened_constructorof(BT)(bc.f.((Tuple.(bc.args))...), Val(BlockLengths))
 end
 
+Base.ndims(::Type{<:AbstractBlockTuple}) = 1  # needed in nested broadcast
+
 # BlockArrays interface
 BlockArrays.blockfirsts(::AbstractBlockTuple{0}) = ()
 function BlockArrays.blockfirsts(bt::AbstractBlockTuple)

test/test_blockedtuple.jl

@@ -58,6 +58,7 @@ using TensorAlgebra: BlockedTuple, blockeachindex, tuplemortar
 
   bt = tuplemortar(((1:2, 1:2), (1:3,)))
   @test length.(bt) == tuplemortar(((2, 2), (3,)))
+  @test length.(length.(bt)) == tuplemortar(((1, 1), (1,)))
 
   # empty blocks
   bt = tuplemortar(((1,), (), (5, 3)))