FluxML/Zygote.jl

Zygote.hessian_reverse for BatchNorm broken on julia v1.11

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#1,531 opened on Oct 11, 2024

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Description

With Zygote v0.6.71 on julia v1.11 I get the following error:

m = Chain(BatchNorm(3), sum)
x = Float32[1 2; 3 4; 5 6]
Zygote.hessian_reverse(m, x)

ERROR: Compiling Tuple{Zygote.Pullback{Tuple{typeof(Base.sym_in), Symbol, Tuple{Symbol, Symbol}}, Any}, Nothing}: UndefRefError: access to undefined reference
Stacktrace:
  [1] macro expansion
    @ ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0 [inlined]
  [2] _pullback(ctx::Zygote.Context{false}, f::Zygote.Pullback{Tuple{…}, Any}, args::Nothing)
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:87
  [3] Pullback
    @ ./namedtuple.jl:399 [inlined]
  [4] _pullback(ctx::Zygote.Context{false}, f::Zygote.Pullback{Tuple{…}, Any}, args::Nothing)
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
  [5] Pullback
    @ ~/.julia/dev/Flux/src/layers/normalise.jl:225 [inlined]
  [6] _pullback(ctx::Zygote.Context{false}, f::Zygote.Pullback{Tuple{…}, Any}, args::FillArrays.Fill{Float32, 2, Tuple{…}})
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
  [7] Pullback
    @ ~/.julia/dev/Flux/src/layers/normalise.jl:354 [inlined]
  [8] _pullback(ctx::Zygote.Context{…}, f::Zygote.Pullback{…}, args::FillArrays.Fill{…})
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
  [9] Pullback
    @ ~/.julia/dev/Flux/src/layers/basic.jl:53 [inlined]
 [10] _pullback(ctx::Zygote.Context{false}, f::Zygote.Pullback{Tuple{…}, Tuple{…}}, args::Float32)
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
 [11] Pullback
    @ ~/.julia/dev/Flux/src/layers/basic.jl:51 [inlined]
 [12] _pullback(ctx::Zygote.Context{false}, f::Zygote.Pullback{Tuple{…}, Tuple{…}}, args::Float32)
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
 [13] FluxML/Flux.jl#78
    @ ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface.jl:91 [inlined]
 [14] _pullback(ctx::Zygote.Context{false}, f::Zygote.var"#78#79"{Zygote.Pullback{Tuple{…}, Tuple{…}}}, args::Float32)
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
 [15] gradient
    @ ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface.jl:148 [inlined]
 [16] _pullback(::Zygote.Context{false}, ::typeof(gradient), ::Chain{Tuple{BatchNorm{…}, typeof(sum)}}, ::Matrix{Float32})
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
 [17] FluxML/Flux.jl#132
    @ ~/.julia/packages/Zygote/Tt5Gx/src/lib/grad.jl:75 [inlined]
 [18] _pullback(ctx::Zygote.Context{false}, f::Zygote.var"#132#133"{Chain{Tuple{…}}}, args::Matrix{Float32})
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
 [19] _apply(::Function, ::Vararg{Any})
    @ Core ./boot.jl:946
 [20] adjoint
    @ ~/.julia/packages/Zygote/Tt5Gx/src/lib/lib.jl:203 [inlined]
 [21] _pullback
    @ ~/.julia/packages/ZygoteRules/M4xmc/src/adjoint.jl:67 [inlined]
 [22] call_composed
    @ ./operators.jl:1054 [inlined]
 [23] call_composed
    @ ./operators.jl:1053 [inlined]
 [24] #_#113
    @ ./operators.jl:1050 [inlined]
 [25] _pullback(::Zygote.Context{…}, ::Base.var"##_#113", ::@Kwargs{}, ::ComposedFunction{…}, ::Matrix{…})
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
 [26] _apply
    @ ./boot.jl:946 [inlined]
 [27] adjoint
    @ ~/.julia/packages/Zygote/Tt5Gx/src/lib/lib.jl:203 [inlined]
 [28] _pullback
    @ ~/.julia/packages/ZygoteRules/M4xmc/src/adjoint.jl:67 [inlined]
 [29] ComposedFunction
    @ ./operators.jl:1050 [inlined]
 [30] _pullback(ctx::Zygote.Context{…}, f::ComposedFunction{…}, args::Matrix{…})
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface2.jl:0
 [31] pullback(f::Function, cx::Zygote.Context{false}, args::Matrix{Float32})
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface.jl:90
 [32] pullback
    @ ~/.julia/packages/Zygote/Tt5Gx/src/compiler/interface.jl:88 [inlined]
 [33] withjacobian(f::Function, args::Matrix{Float32})
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/lib/grad.jl:141
 [34] jacobian
    @ ~/.julia/packages/Zygote/Tt5Gx/src/lib/grad.jl:128 [inlined]
 [35] hessian_reverse(f::Chain{Tuple{BatchNorm{…}, typeof(sum)}}, x::Matrix{Float32})
    @ Zygote ~/.julia/packages/Zygote/Tt5Gx/src/lib/grad.jl:75
 [36] top-level scope
    @ REPL[3]:1
Some type information was truncated. Use `show(err)` to see complete types.

It is specific to BatchNorm, since this works instead

m = Chain(Dense(3=>3), sum)
x = Float32[1 2; 3 4; 5 6]
Zygote.hessian_reverse(m, x)

Found in FluxML/Flux.jl#2492

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Issue type
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Julia programmingZygote internals
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Research direction
Investigate the error in Zygote.hessian reverse for BatchNorm. The stack trace indicates issues in Pullback and sym in. Check for Julia v1.11 compatibility and examine the Zygote compiler interface. Also review the referenced Flux issue (FluxML/Flux.jl#2492) for additional context.
Zygote.hessian_reverse for BatchNorm broken on julia v1.11 · FluxML/Zygote.jl#1531 | Good First Issue