|
| 1 | + |
| 2 | +using Test |
| 3 | +using Random |
| 4 | +using LinearAlgebra |
| 5 | +using TensorKit |
| 6 | +using Mooncake |
| 7 | +using Accessors |
| 8 | +using PEPSKit |
| 9 | + |
| 10 | +using MatrixAlgebraKit: TruncatedAlgorithm, diagview |
| 11 | + |
| 12 | +# Gauge-invariant loss function |
| 13 | +function lossfun(A, alg, R = randn(space(A)), trunc = notrunc()) |
| 14 | + alg = @set alg.fwd_alg = TruncatedAlgorithm(alg.fwd_alg, trunc) |
| 15 | + D, V, = eigh_trunc(project_hermitian(A), alg) |
| 16 | + return real(dot(R, V * V')) + dot(D, D) # Overlap with random tensor R is gauge-invariant and differentiable |
| 17 | +end |
| 18 | + |
| 19 | +dtype = ComplexF64 |
| 20 | +n = 20 |
| 21 | +χ = 10 |
| 22 | +trunc = truncspace(ℂ^χ) |
| 23 | +rtol = 1.0e-9 |
| 24 | +Random.seed!(123456789) |
| 25 | +r = randn(dtype, ℂ^n, ℂ^n) |
| 26 | +r = 0.5 * (r + r') # make r Hermitian |
| 27 | +R = randn(space(r)) |
| 28 | +R = 0.5 * (R + R') |
| 29 | + |
| 30 | +full_alg = EighAdjoint(; fwd_alg = (; alg = :QRIteration), rrule_alg = (; alg = :FullPullback)) |
| 31 | +trunc_alg = EighAdjoint(; fwd_alg = (; alg = :QRIteration), rrule_alg = (; alg = :TruncPullback)) |
| 32 | +iter_alg = EighAdjoint(; fwd_alg = (; alg = :Lanczos), rrule_alg = (; alg = :TruncPullback)) |
| 33 | + |
| 34 | +@testset "Non-truncated eigh" begin |
| 35 | + full_lossfun = A -> lossfun(A, full_alg, R) |
| 36 | + trunc_lossfun = A -> lossfun(A, trunc_alg, R) |
| 37 | + iter_lossfun = A -> lossfun(A, iter_alg, R) |
| 38 | + |
| 39 | + full_rrule = Mooncake.build_rrule(full_lossfun, r) |
| 40 | + trunc_rrule = Mooncake.build_rrule(trunc_lossfun, r) |
| 41 | + iter_rrule = Mooncake.build_rrule(iter_lossfun, r) |
| 42 | + |
| 43 | + l_full, g_full = Mooncake.value_and_gradient!!(full_rrule, full_lossfun, r) |
| 44 | + l_trunc, g_trunc = Mooncake.value_and_gradient!!(trunc_rrule, trunc_lossfun, r) |
| 45 | + l_iter, g_iter = Mooncake.value_and_gradient!!(iter_rrule, iter_lossfun, r) |
| 46 | + |
| 47 | + @test l_full ≈ l_trunc ≈ l_iter |
| 48 | + @test g_full[2] ≈ g_trunc[2] rtol = rtol |
| 49 | + @test g_full[2] ≈ g_iter[2] rtol = rtol |
| 50 | + @test g_trunc[2] ≈ g_iter[2] rtol = rtol |
| 51 | +end |
| 52 | + |
| 53 | +@testset "Truncated eigh with χ=$χ" begin |
| 54 | + full_lossfun = A -> lossfun(A, full_alg, R, trunc) |
| 55 | + trunc_lossfun = A -> lossfun(A, trunc_alg, R, trunc) |
| 56 | + iter_lossfun = A -> lossfun(A, iter_alg, R, trunc) |
| 57 | + |
| 58 | + full_rrule = Mooncake.build_rrule(full_lossfun, r) |
| 59 | + trunc_rrule = Mooncake.build_rrule(trunc_lossfun, r) |
| 60 | + iter_rrule = Mooncake.build_rrule(iter_lossfun, r) |
| 61 | + |
| 62 | + l_full, g_full = Mooncake.value_and_gradient!!(full_rrule, full_lossfun, r) |
| 63 | + l_trunc, g_trunc = Mooncake.value_and_gradient!!(trunc_rrule, trunc_lossfun, r) |
| 64 | + l_iter, g_iter = Mooncake.value_and_gradient!!(iter_rrule, iter_lossfun, r) |
| 65 | + |
| 66 | + @test l_full ≈ l_trunc ≈ l_iter |
| 67 | + @test g_full[2] ≈ g_trunc[2] rtol = rtol |
| 68 | + @test g_full[2] ≈ g_iter[2] rtol = rtol |
| 69 | + @test g_trunc[2] ≈ g_iter[2] rtol = rtol |
| 70 | +end |
| 71 | + |
| 72 | +@testset "Truncated eigh broadening for $(alg.rrule_alg)" for alg in [full_alg, trunc_alg] |
| 73 | + d, v = eigh_full(r) |
| 74 | + d.data[1:2:n] .= d.data[2:2:n] # make every eigenvalue two-fold degenerate |
| 75 | + r_degen = v * d * v' |
| 76 | + |
| 77 | + no_broadening_no_cutoff_alg = @set alg.rrule_alg.degeneracy_atol = 1.0e-30 |
| 78 | + small_broadening_alg = @set alg.rrule_alg.degeneracy_atol = 1.0e-13 |
| 79 | + |
| 80 | + only_lossfun = A -> lossfun(A, alg, R, trunc) |
| 81 | + no_broadening_lossfun = A -> lossfun(A, no_broadening_no_cutoff_alg, R, trunc) |
| 82 | + small_broadening_lossfun = A -> lossfun(A, small_broadening_alg, R, trunc) |
| 83 | + |
| 84 | + only_rrule = Mooncake.build_rrule(only_lossfun, r_degen) |
| 85 | + no_broadening_rrule = Mooncake.build_rrule(no_broadening_lossfun, r_degen) |
| 86 | + small_broadening_rrule = Mooncake.build_rrule(small_broadening_lossfun, r_degen) |
| 87 | + |
| 88 | + l_only_cutoff, g_only_cutoff = Mooncake.value_and_gradient!!(only_rrule, only_lossfun, r_degen) # cutoff sets degenerate difference to zero |
| 89 | + l_no_broadening_no_cutoff, g_no_broadening_no_cutoff = Mooncake.value_and_gradient!!( # degenerate singular value differences lead to divergent contributions |
| 90 | + no_broadening_rrule, no_broadening_lossfun, r_degen, |
| 91 | + ) |
| 92 | + l_small_broadening, g_small_broadening = Mooncake.value_and_gradient!!( # broadening smoothens divergent contributions |
| 93 | + small_broadening_rrule, small_broadening_lossfun, r_degen, |
| 94 | + ) |
| 95 | + |
| 96 | + @test l_only_cutoff ≈ l_no_broadening_no_cutoff ≈ l_small_broadening |
| 97 | + @test norm(g_no_broadening_no_cutoff[2] - g_small_broadening[2]) > 1.0e-2 # divergences mess up the gradient |
| 98 | + @test g_only_cutoff[2] ≈ g_small_broadening[2] rtol = rtol # cutoff and broadening have similar effect |
| 99 | +end |
| 100 | + |
| 101 | +symm_m, symm_n = 18, 24 |
| 102 | +symm_space = Z2Space(0 => symm_m, 1 => symm_n) |
| 103 | +symm_trspace = truncspace(Z2Space(0 => symm_m ÷ 2, 1 => symm_n ÷ 3)) |
| 104 | +symm_r = randn(dtype, symm_space, symm_space) |
| 105 | +symm_r = 0.5 * (symm_r + symm_r') |
| 106 | +symm_R = randn(dtype, space(symm_r)) |
| 107 | +symm_R = 0.5 * (symm_R + symm_R') |
| 108 | + |
| 109 | +@testset "IterEig of symmetric tensors" begin |
| 110 | + full_lossfun = A -> lossfun(A, full_alg, symm_R) |
| 111 | + trunc_lossfun = A -> lossfun(A, trunc_alg, symm_R) |
| 112 | + iter_lossfun = A -> lossfun(A, iter_alg, symm_R) |
| 113 | + |
| 114 | + full_rrule = Mooncake.build_rrule(full_lossfun, symm_r) |
| 115 | + trunc_rrule = Mooncake.build_rrule(trunc_lossfun, symm_r) |
| 116 | + iter_rrule = Mooncake.build_rrule(iter_lossfun, symm_r) |
| 117 | + |
| 118 | + l_full, g_full = Mooncake.value_and_gradient!!(full_rrule, full_lossfun, symm_r) |
| 119 | + l_trunc, g_trunc = Mooncake.value_and_gradient!!(trunc_rrule, trunc_lossfun, symm_r) |
| 120 | + l_iter, g_iter = Mooncake.value_and_gradient!!(iter_rrule, iter_lossfun, symm_r) |
| 121 | + |
| 122 | + @test l_full ≈ l_trunc ≈ l_iter |
| 123 | + @test g_full[2] ≈ g_trunc[2] rtol = rtol |
| 124 | + @test g_full[2] ≈ g_iter[2] rtol = rtol |
| 125 | + @test g_trunc[2] ≈ g_iter[2] rtol = rtol |
| 126 | + |
| 127 | + full_lossfun = A -> lossfun(A, full_alg, symm_R, symm_trspace) |
| 128 | + trunc_lossfun = A -> lossfun(A, trunc_alg, symm_R, symm_trspace) |
| 129 | + iter_lossfun = A -> lossfun(A, iter_alg, symm_R, symm_trspace) |
| 130 | + |
| 131 | + full_rrule = Mooncake.build_rrule(full_lossfun, symm_r) |
| 132 | + trunc_rrule = Mooncake.build_rrule(trunc_lossfun, symm_r) |
| 133 | + iter_rrule = Mooncake.build_rrule(iter_lossfun, symm_r) |
| 134 | + |
| 135 | + l_full_tr, g_full_tr = Mooncake.value_and_gradient!!(full_rrule, full_lossfun, symm_r) |
| 136 | + l_trunc_tr, g_trunc_tr = Mooncake.value_and_gradient!!(trunc_rrule, trunc_lossfun, symm_r) |
| 137 | + l_iter_tr, g_iter_tr = Mooncake.value_and_gradient!!(iter_rrule, iter_lossfun, symm_r) |
| 138 | + @test l_full_tr ≈ l_trunc_tr ≈ l_iter_tr |
| 139 | + @test g_full_tr[2] ≈ g_trunc_tr[2] rtol = rtol |
| 140 | + @test g_full_tr[2] ≈ g_iter_tr[2] rtol = rtol |
| 141 | + @test g_trunc_tr[2] ≈ g_iter_tr[2] rtol = rtol |
| 142 | + |
| 143 | + iter_alg_fallback = @set iter_alg.fwd_alg.fallback_threshold = 0.4 # Do dense decomposition in one block, sparse one in the other |
| 144 | + fb_lossfun = A -> lossfun(A, iter_alg_fallback, symm_R, symm_trspace) |
| 145 | + fb_rrule = Mooncake.build_rrule(fb_lossfun, symm_r) |
| 146 | + l_iter_fb, g_iter_fb = Mooncake.value_and_gradient!!(fb_rrule, fb_lossfun, symm_r) |
| 147 | + @test l_iter_fb ≈ l_trunc_tr ≈ l_full_tr |
| 148 | + @test g_full_tr[2] ≈ g_iter_fb[2] rtol = rtol |
| 149 | + @test g_trunc_tr[2] ≈ g_iter_fb[2] rtol = rtol |
| 150 | +end |
| 151 | +#= |
| 152 | +@testset "Truncated symmetric eigh broadening for $(alg.rrule_alg)" for alg in [full_alg, trunc_alg] |
| 153 | + d, v = eigh_full(symm_r) |
| 154 | + # make every singular value in the 0-sector three-fold degenerate |
| 155 | + b0 = diagview(block(d, Z2Irrep(0))) |
| 156 | + b0[1:3:symm_m] .= b0[3:3:symm_m] |
| 157 | + b0[2:3:symm_m] .= b0[3:3:symm_m] |
| 158 | + # make every singular value in the 1-sector two-fold degenerate |
| 159 | + b1 = diagview(block(d, Z2Irrep(1))) |
| 160 | + b1[1:2:symm_n] .= b1[2:2:symm_n] |
| 161 | + symm_r_degen = v * d * v' |
| 162 | +
|
| 163 | + no_broadening_no_cutoff_alg = @set alg.rrule_alg.degeneracy_atol = 1.0e-30 |
| 164 | + small_broadening_alg = @set alg.rrule_alg.degeneracy_atol = 1.0e-13 |
| 165 | +
|
| 166 | + l_only_cutoff, g_only_cutoff = withgradient( |
| 167 | + A -> lossfun(A, alg, symm_R, symm_trspace), symm_r_degen |
| 168 | + ) # cutoff sets degenerate difference to zero |
| 169 | + l_no_broadening_no_cutoff, g_no_broadening_no_cutoff = withgradient( # degenerate singular value differences lead to divergent contributions |
| 170 | + A -> lossfun(A, no_broadening_no_cutoff_alg, symm_R, symm_trspace), |
| 171 | + symm_r_degen, |
| 172 | + ) |
| 173 | + l_small_broadening, g_small_broadening = withgradient( # broadening smoothens divergent contributions |
| 174 | + A -> lossfun(A, small_broadening_alg, symm_R, symm_trspace), |
| 175 | + symm_r_degen, |
| 176 | + ) |
| 177 | +
|
| 178 | + @test l_only_cutoff ≈ l_no_broadening_no_cutoff ≈ l_small_broadening |
| 179 | + @test norm(g_no_broadening_no_cutoff[1] - g_small_broadening[1]) > 1.0e-2 # divergences mess up the gradient |
| 180 | + @test g_only_cutoff[1] ≈ g_small_broadening[1] rtol = rtol # cutoff and broadening have similar effect |
| 181 | +end=# |
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