Fix creation of dense similar for linalg

Author: kshyatt

src/auxiliary/blockarrays.jl

@@ -1,3 +1,12 @@
+similar_dense(::Type{Vector{T}}, sz::NTuple{N, Ti}) where {T,N,Ti} = Array{T, N}(undef, sz) 
+similar_dense(::Type{TA}, sz) where {T,N,P,TA<:Base.SubArray{T,N,P}} = similar_dense(P, sz)
+similar_dense(::Type{TA}, sz) where {T,N,P,TA<:Base.ReshapedArray{T,N,P}} = similar_dense(P, sz)
+similar_dense(::Type{TA}, sz) where {T,N,TA<:AbstractArray{T,N}} = TA(undef, sz)
+function similar_dense(A::BlockMatrix{T, R}) where {T, R}
+    Adense = similar_dense(eltype(R), size(A))
+    return Adense
+end
+
 function copy_dense!(Adense, A)
     for block_index in Iterators.product(blockaxes(A)...)
         a = view(A, block_index...)

src/linalg/factorizations.jl

@@ -25,7 +25,8 @@ for f! in (
     )
     @eval function MAK.$f!(t::AbstractBlockTensorMap, F, alg::AbstractAlgorithm)
         TensorKit.foreachblock(t, F...) do _, (tblock, Fblocks...)
-            Fblocks′ = MAK.$f!(copy_dense!(similar(tblock, size(tblock)), tblock), alg)
+            dense_block = similar_dense(tblock)
+            Fblocks′ = MAK.$f!(copy_dense!(dense_block, tblock), alg)
             # deal with the case where the output is not in-place
             for (b′, b) in zip(Fblocks′, Fblocks)
                 b === b′ || copy!(b, b′)
@@ -44,7 +45,8 @@ for f! in (
     )
     @eval function MAK.$f!(t::AbstractBlockTensorMap, N, alg::AbstractAlgorithm)
         TensorKit.foreachblock(t, N) do _, (tblock, Nblock)
-            Nblock′ = MAK.$f!(copy_dense!(similar(tblock, size(tblock)), tblock), alg)
+            dense_block = similar_dense(tblock)
+            Nblock′ = MAK.$f!(copy_dense!(dense_block, tblock), alg)
             # deal with the case where the output is not the same as the input
             Nblock === Nblock′ || copy!(Nblock, Nblock′)
             return nothing