Using InfiniteSum{ITensor} instead of InfiniteSum{MPO} in some examples

Author: mtfishman

examples/vumps/vumps_hubbard_extended.jl

@@ -9,7 +9,7 @@ maxdim = 30 # Maximum bond dimension
 cutoff = 1e-6 # Singular value cutoff when increasing the bond dimension
 max_vumps_iters = 200 # Maximum number of iterations of the VUMPS algorithm at each bond dimension
 outer_iters = 5 # Number of times to increase the bond dimension
-localham_type = ITensor
+localham_type = ITensor # or MPO
 
 model_params = (t=1.0, U=10.0, V=0.0)
 
@@ -19,6 +19,9 @@ model_params = (t=1.0, U=10.0, V=0.0)
 
 N = 2 # Unit cell size
 
+@show N
+@show localham_type
+
 function electron_space_shift(q̃nf, q̃sz)
   return [
     QN(("Nf", 0 - q̃nf, -1), ("Sz", 0 - q̃sz)) => 1,
@@ -53,9 +56,9 @@ subspace_expansion_kwargs = (cutoff=cutoff, maxdim=maxdim)
 # a larger bond dimension)
 
 println("\nRun VUMPS on initial product state, unit cell size $N")
-ψ = vumps(H, ψ; vumps_kwargs...)
+ψ = @time vumps(H, ψ; vumps_kwargs...)
 
-for _ in 1:outer_iters
+@time for _ in 1:outer_iters
   println("\nIncrease bond dimension")
   global ψ = subspace_expansion(ψ, H; subspace_expansion_kwargs...)
   println("Run VUMPS with new bond dimension")

examples/vumps/vumps_ising.jl

@@ -15,7 +15,7 @@ solver_tol = (x -> x / 100) # Tolerance for the local solver (eigsolve in VUMPS
 multisite_update_alg = "parallel" # Choose between ["sequential", "parallel"]. Only parallel works with TDVP.
 conserve_qns = true # Whether or not to conserve spin parity
 nsite = 2 # Number of sites in the unit cell
-localham_type = MPO # Can choose `ITensor` or `MPO`
+localham_type = ITensor # Can choose `ITensor` or `MPO`
 
 # Parameters of the transverse field Ising model
 model_params = (J=1.0, h=0.9)

examples/vumps/vumps_localham.jl

@@ -22,7 +22,7 @@ h = 1.5
 model = Model(:ising)
 
 # Form the Hamiltonian
-Σ∞h = InfiniteSum{MPO}(model, s; J=J, h=h)
+Σ∞h = InfiniteSum{ITensor}(model, s; J=J, h=h)
 
 χ = 6
 ψ = InfiniteMPS(s; space=χ)

examples/vumps/vumps_localham_qns.jl

@@ -31,7 +31,7 @@ energy_finite, ψfinite = dmrg(Hfinite, ψfinite, sweeps)
 @show energy_finite / Nfinite
 
 # Form the Hamiltonian
-Σ∞h = InfiniteSum{MPO}(model, s; model_kwargs...)
+Σ∞h = InfiniteSum{ITensor}(model, s; model_kwargs...)
 
 d = 1
 χ = [QN("SzParity", 1, 2) => d, QN("SzParity", 0, 2) => d]