[ITensors] Make sure polar preserves the input element type (#1375)

ITensor · Apr 2, 2024 · 7902cd4 · 7902cd4
1 parent ce5203b
commit 7902cd4
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diff --git a/src/tensor_operations/matrix_decomposition.jl b/src/tensor_operations/matrix_decomposition.jl
@@ -555,7 +555,7 @@ function polar(A::ITensor, Linds...)
   U, S, V = svd(A, Linds...)
   u = commoninds(S, U)
   v = commoninds(S, V)
-  δᵤᵥ′ = δ(u..., v'...)
+  δᵤᵥ′ = δ(eltype(A), u..., v'...)
   Q = U * δᵤᵥ′ * V'
   P = dag(V') * dag(δᵤᵥ′) * S * V
   return Q, P, commoninds(Q, P)

diff --git a/test/base/test_itensor.jl b/test/base/test_itensor.jl
@@ -1512,7 +1512,12 @@ end
 
       @testset "Test polar decomposition of an ITensor" begin
         U, P, u = polar(A, (k, l))
+
+        @test eltype(U) == eltype(A)
+        @test eltype(P) == eltype(A)
+
         @test A ≈ U * P atol = atol
+
         #Note: this is only satisfied when left dimensions
         #are greater than right dimensions
         UUᵀ = U * dag(prime(U, u))