Merge branch 'master' into sector

Author: lkdvos

test/excis.jl

@@ -0,0 +1,100 @@
+using MPSKit, TensorKit
+import LinearAlgebra.eigvals
+using MPSKit: max_virtualspaces
+
+V = U1Space(i => 1 for i in 0:1)
+O = randn(V^2 ← V^2)
+O += O'  # Hermitian
+
+N = 3
+H = FiniteMPOHamiltonian(fill(V, N), (i, i + 1) => O for i in 1:(N - 1));
+
+h = convert(TensorMap, H);
+
+sectors = collect(blocksectors(h))
+sec = U1Irrep(1)
+@assert sec in sectors
+num = 10
+vals1 = eigvals(block(h, sec))
+vals2 = eigvals(h)[sec]
+@assert vals1 ≈ vals2
+vals3, vecs = exact_diagonalization(H; sector=(sec), num);
+vals1
+vals3
+
+right = U1Space(sec => 1)
+max_virtualspaces(physicalspace(H); right)
+
+psi_full = rand(oneunit(V) * V^N ← right);
+dim(space(psi_full))
+psi = MPSKit.decompose_localmps(psi_full);
+left_virtualspace.(psi)
+
+left_virtualspace.(vecs[1].AL)
+right_virtualspace.(vecs[1].AL)
+max_virtualspaces(physicalspace(H); right)
+psi1 = FiniteMPS(physicalspace(H), max_virtualspaces(physicalspace(H))[2:(end - 1)])
+psi1, = find_groundstate(psi1, H);
+psi2 = FiniteMPS(physicalspace(H), max_virtualspaces(physicalspace(H); right)[2:(end - 1)];
+                 right)
+left_virtualspace.(psi2.AL)
+right_virtualspace.(psi2.AL)
+
+psi2, = find_groundstate(psi2, H);
+expectation_value(psi2, H)
+
+Es, Bs = excitations(H, QuasiparticleAnsatz(), FiniteMPS(psi); sector=sec);
+@inferred excitations(H, QuasiparticleAnsatz(), FiniteMPS(psi); sector=sec);
+
+Es .+ expectation_value(psi1, H)
+
+vals1
+vals3
+
+psi2
+using TestEnv
+using Test
+TestEnv.activate()
+include("setup.jl")
+using .TestSetup
+using TensorKit, MPSKit
+using MPSKit: Multiline
+using KrylovKit
+
+H = repeat(TestSetup.sixvertex(), 2)
+ψ = InfiniteMPS([ℂ^2, ℂ^2], [ℂ^10, ℂ^10])
+ψ, envs, _ = leading_boundary(ψ, H,
+                              VUMPS(; maxiter=400, tol=1e-10))
+energies, ϕs = @inferred excitations(H, QuasiparticleAnsatz(),
+                                     [0.0, Float64(pi / 2)], ψ,
+                                     envs; verbosity=0)
+@test abs(energies[1]) > abs(energies[2]) # has a minimum at pi/2
+alg = QuasiparticleAnsatz()
+ps = [0.0, Float64(pi / 2)]
+excitations(H, alg, ps, ψ, envs; verbosity=0);
+using Cthulhu
+Hm = convert(MultilineMPO, H);
+psim = convert(MultilineMPS, ψ);
+envs = environments(psim, Hm);
+excitations(Hm, alg, ps[1], psim, envs, psim, envs; verbosity=0);
+
+@descend excitations(Hm, alg, ps[1], psim, envs, psim, envs);
+
+qp = Multiline([LeftGaugedQP(rand, psim[1], psim[1]; sector=one(sectortype(psim[1])),
+                             momentum=ps[1])]);
+excitations(Hm, alg, qp, envs, envs; num=1);
+
+@descend excitations(Hm, alg, qp, envs, envs; num=1);
+@code_warntype excitations(Hm, alg, qp, envs, envs; num=1);
+
+Heff = MPSKit.EffectiveExcitationHamiltonian(H, envs[1], envs[1], fill(1.0, length(H)));
+Heffs = Multiline([Heff]);
+@code_warntype KrylovKit.apply(Heff, qp[1])
+@descend KrylovKit.apply(Heff, qp[1])
+
+KrylovKit.apply(Multiline([Heff]), qp);
+@code_warntype KrylovKit.apply(Heffs, qp);
+
+@descend eigsolve(Heffs, qp, 1, :LM, Lanczos());
+@code_warntype eigsolve(Heffs, qp, 1, :LM);
+@descend eigsolve(Heffs, qp, 1, :LM);