From d41cbbc6ed980baedb22befbf84a42a07f658dda Mon Sep 17 00:00:00 2001
From: Lukas Devos <ldevos98@gmail.com>
Date: Mon, 30 Dec 2024 15:19:02 +0100
Subject: [PATCH] update TensorKit compat

---
 Project.toml                 |  2 +-
 src/linalg/factorizations.jl | 35 ++++++++++++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/Project.toml b/Project.toml
index f26ac20..d4f2344 100644
--- a/Project.toml
+++ b/Project.toml
@@ -21,7 +21,7 @@ LinearAlgebra = "1"
 Random = "1"
 Strided = "2"
 SafeTestsets = "0.1"
-TensorKit = "0.13.2"
+TensorKit = "0.13.2, 0.14"
 TensorOperations = "5"
 Test = "1"
 TestExtras = "0.2"
diff --git a/src/linalg/factorizations.jl b/src/linalg/factorizations.jl
index d68742a..8281e5a 100644
--- a/src/linalg/factorizations.jl
+++ b/src/linalg/factorizations.jl
@@ -213,6 +213,27 @@ function TK.tsvd!(t::SparseBlockTensorMap; kwargs...)
     return tsvd!(BlockTensorMap(t); kwargs...)
 end
 
+function TK._tsvd!(
+    t::BlockTensorMap, alg::Union{SVD,SDD}, trunc::TruncationScheme, p::Real=2
+)
+    # early return
+    if isempty(blocksectors(t))
+        truncerr = zero(real(scalartype(t)))
+        return TK._empty_svdtensors(t)..., truncerr
+    end
+
+    # compute SVD factorization for each block
+    S = spacetype(t)
+    SVDdata, dims = TK._compute_svddata!(t, alg)
+    Σdata = SectorDict(c => Σ for (c, (U, Σ, V)) in SVDdata)
+    truncdim = TK._compute_truncdim(Σdata, trunc, p)
+    truncerr = TK._compute_truncerr(Σdata, truncdim, p)
+
+    # construct output tensors
+    U, Σ, V⁺ = TK._create_svdtensors(t, SVDdata, truncdim)
+    return U, Σ, V⁺, truncerr
+end
+
 function TK._compute_svddata!(t::AbstractBlockTensorMap, alg::Union{SVD,SDD})
     InnerProductStyle(t) === EuclideanInnerProduct() || throw_invalid_innerproduct(:tsvd!)
     I = sectortype(t)
@@ -225,7 +246,6 @@ function TK._compute_svddata!(t::AbstractBlockTensorMap, alg::Union{SVD,SDD})
     SVDdata = SectorDict(generator)
     return SVDdata, dims
 end
-
 function TK._create_svdtensors(t::AbstractBlockTensorMap, SVDdata, dims)
     S = spacetype(t)
     W = S(dims)
@@ -241,3 +261,16 @@ function TK._create_svdtensors(t::AbstractBlockTensorMap, SVDdata, dims)
     end
     return U, Σ, V⁺
 end
+
+function TK._empty_svdtensors(t::AbstractBlockTensorMap)
+    T = scalartype(t)
+    S = spacetype(t)
+    I = sectortype(t)
+    dims = SectorDict{I,Int}()
+    W = S(dims)
+
+    U = similar(t, codomain(t) ← W)
+    Σ = similar(t, real(T), W ← W)
+    V⁺ = similar(t, W ← domain(t))
+    return U, Σ, V⁺
+end