From 3275ffbe04a51a96d83f871415d22a5a3c28c486 Mon Sep 17 00:00:00 2001
From: Lukas <37111893+lkdvos@users.noreply.github.com>
Date: Tue, 2 Jul 2024 15:22:19 +0200
Subject: [PATCH] Soften type restrictions on tsvd kwargs (#134)

* Soften type restrictions on tsvd kwargs

* Fix spaces in truncated svd to non-dual
---
 src/tensors/factorizations.jl | 35 ++++++++++++-----------------------
 1 file changed, 12 insertions(+), 23 deletions(-)

diff --git a/src/tensors/factorizations.jl b/src/tensors/factorizations.jl
index 524e2760..6b325d48 100644
--- a/src/tensors/factorizations.jl
+++ b/src/tensors/factorizations.jl
@@ -246,10 +246,7 @@ function LinearAlgebra.isposdef(t::AbstractTensorMap, (p₁, p₂)::Index2Tuple)
     return isposdef!(permute(t, (p₁, p₂); copy=true))
 end
 
-function tsvd(t::AbstractTensorMap; trunc::TruncationScheme=NoTruncation(),
-              p::Real=2, alg::Union{SVD,SDD}=SDD())
-    return tsvd!(copy(t); trunc=trunc, p=p, alg=alg)
-end
+tsvd(t::AbstractTensorMap; kwargs...) = tsvd!(copy(t); kwargs...)
 function leftorth(t::AbstractTensorMap; alg::OFA=QRpos(), kwargs...)
     return leftorth!(copy(t); alg=alg, kwargs...)
 end
@@ -413,19 +410,17 @@ end
 #------------------------------#
 # Singular value decomposition #
 #------------------------------#
-function tsvd!(t::AdjointTensorMap;
-               trunc::TruncationScheme=NoTruncation(),
-               p::Real=2,
-               alg::Union{SVD,SDD}=SDD())
+function tsvd!(t::AdjointTensorMap; trunc=NoTruncation(), p::Real=2, alg=SDD())
     u, s, vt, err = tsvd!(adjoint(t); trunc=trunc, p=p, alg=alg)
     return adjoint(vt), adjoint(s), adjoint(u), err
 end
+function tsvd!(t::TensorMap; trunc=NoTruncation(), p::Real=2, alg=SDD())
+    return _tsvd!(t, alg, trunc, p)
+end
 
-function tsvd!(t::TensorMap;
-               trunc::TruncationScheme=NoTruncation(),
-               p::Real=2,
-               alg::Union{SVD,SDD}=SDD())
-    #early return
+# implementation dispatches on algorithm
+function _tsvd!(t, alg::Union{SVD,SDD}, trunc::TruncationScheme, p::Real=2)
+    # early return
     if isempty(blocksectors(t))
         truncerr = zero(real(scalartype(t)))
         return _empty_svdtensors(t)..., truncerr
@@ -433,19 +428,13 @@ function tsvd!(t::TensorMap;
 
     S = spacetype(t)
     Udata, Σdata, Vdata, dims = _compute_svddata!(t, alg)
-    if !isa(trunc, NoTruncation)
+    if trunc isa NoTruncation
+        truncerr = abs(zero(scalartype(t)))
+    else
         Σdata, truncerr = _truncate!(Σdata, trunc, p)
         Udata, Σdata, Vdata, dims = _implement_svdtruncation!(t, Udata, Σdata, Vdata, dims)
-        W = S(dims)
-    else
-        truncerr = abs(zero(scalartype(t)))
-        W = S(dims)
-        if length(domain(t)) == 1 && domain(t)[1] ≅ W
-            W = domain(t)[1]
-        elseif length(codomain(t)) == 1 && codomain(t)[1] ≅ W
-            W = codomain(t)[1]
-        end
     end
+    W = S(dims)
     return _create_svdtensors(t, Udata, Σdata, Vdata, W)..., truncerr
 end