cg! is type unstable

[mohamed82008]

The following code is type unstable:

T = Float64
n = 10
A = rand(T, n, n)
A = A' * A + I
b = rand(T, n)
tol = √eps(real(T))
x0 = randn(size(b))
xJAC, hJAC = cg!(copy(x0), A, b; Pl=Identity(), tol=tol, maxiter=100, log=true)
@code_warntype cg!(copy(x0), A, b; Pl=Identity(), tol=tol, maxiter=100, log=true)

Here is the output:

Variables:
  #unused# <optimized out>
  #temp#@_2::Array{Any,1}
  ::IterativeSolvers.#cg!
  x::Array{Float64,1}
  A::Array{Float64,2}
  b::Array{Float64,1}
  #temp#@_7::Int64
  #temp#@_8::Int64
  #temp#@_9::Any
  #temp#@_10::Int64
  tol::Any
  maxiter::Any
  log::Bool
  verbose::Bool
  Pl::Any
  #temp#@_16::Bool
  #temp#@_17::Bool
  #temp#@_18::Bool
  kwargs...::Array{Any,1}

Body:
  begin
      NewvarNode(:(tol::Any))
      NewvarNode(:(maxiter::Any))
      NewvarNode(:(Pl::Any))
      #temp#@_16::Bool = true
      #temp#@_17::Bool = true
      log::Bool = false
      verbose::Bool = false
      #temp#@_18::Bool = true
      kwargs...::Array{Any,1} = $(Expr(:foreigncall, :(:jl_alloc_array_1d), Array{Any,1}, svec(Any, Int64), Array{Any,1}, 0, 0, 0))
      SSAValue(3) = (Base.arraylen)(#temp#@_2::Array{Any,1})::Int64
      SSAValue(4) = (Base.select_value)((Base.sle_int)(0, 1)::Bool, (Base.ashr_int)(SSAValue(3), (Base.bitcast)(UInt64, 1))::Int64, (Base.shl_int)(SSAValue(3), (Base.bitcast)(UInt64, (Base.neg_int)(1)::Int64))::Int64)::Int64
      SSAValue(5) = (Base.select_value)((Base.sle_int)(1, SSAValue(4))::Bool, SSAValue(4), (Base.sub_int)(1, 1)::Int64)::Int64
      #temp#@_10::Int64 = 1
      14:
      unless (Base.not_int)((#temp#@_10::Int64 === (Base.add_int)(SSAValue(5), 1)::Int64)::Bool)::Bool goto 48
      SSAValue(6) = #temp#@_10::Int64
      SSAValue(7) = (Base.add_int)(#temp#@_10::Int64, 1)::Int64
      #temp#@_7::Int64 = SSAValue(6)
      #temp#@_10::Int64 = SSAValue(7)
      #temp#@_8::Int64 = (Base.sub_int)((Base.mul_int)(#temp#@_7::Int64, 2)::Int64, 1)::Int64
      #temp#@_9::Any = (Core.arrayref)(#temp#@_2::Array{Any,1}, #temp#@_8::Int64)::Any
      unless (#temp#@_9::Any === :Pl)::Bool goto 26
      Pl::Any = (Core.arrayref)(#temp#@_2::Array{Any,1}, (Base.add_int)(#temp#@_8::Int64, 1)::Int64)::Any
      #temp#@_18::Bool = false
      goto 46
      26:
      unless (#temp#@_9::Any === :verbose)::Bool goto 30
      verbose::Bool = (Core.typeassert)((Core.arrayref)(#temp#@_2::Array{Any,1}, (Base.add_int)(#temp#@_8::Int64, 1)::Int64)::Any, IterativeSolvers.Bool)::Bool
      goto 46
      30:
      unless (#temp#@_9::Any === :log)::Bool goto 34
      log::Bool = (Core.typeassert)((Core.arrayref)(#temp#@_2::Array{Any,1}, (Base.add_int)(#temp#@_8::Int64, 1)::Int64)::Any, IterativeSolvers.Bool)::Bool
      goto 46
      34:
      unless (#temp#@_9::Any === :maxiter)::Bool goto 39
      maxiter::Any = (Core.arrayref)(#temp#@_2::Array{Any,1}, (Base.add_int)(#temp#@_8::Int64, 1)::Int64)::Any
      #temp#@_17::Bool = false
      goto 46
      39:
      unless (#temp#@_9::Any === :tol)::Bool goto 44
      tol::Any = (Core.arrayref)(#temp#@_2::Array{Any,1}, (Base.add_int)(#temp#@_8::Int64, 1)::Int64)::Any
      #temp#@_16::Bool = false
      goto 46
      44:
      $(Expr(:foreigncall, :(:jl_array_ptr_1d_push), Void, svec(Any, Any), :(kwargs...), 0, :((Core.tuple)(#temp#@_9, (Core.arrayref)(#temp#@_2, (Base.add_int)(#temp#@_8, 1)::Int64))::Tuple{Any,Any}), 0))
      46:
      goto 14
      48:
      unless #temp#@_16::Bool goto 51
      tol::Any = (Base.Math.sqrt_llvm)(2.220446049250313e-16)::Float64
      51:
      unless #temp#@_17::Bool goto 54
      maxiter::Any = (Base.arraysize)(A::Array{Float64,2}, 2)::Int64
      54:
      unless #temp#@_18::Bool goto 57
      Pl::Any = $(QuoteNode(IterativeSolvers.Identity()))
      57:
      return (IterativeSolvers.#cg!#39)(tol::Any, maxiter::Any, log::Bool, verbose::Bool, Pl::Any, kwargs...::Array{Any,1}, ::IterativeSolvers.#cg!, x::Array{Float64,1}, A::Array{Float64,2}, b::Array{Float64,1})::Union{Array{Float64,1}, Tuple{Array{Float64,1},IterativeSolvers.ConvergenceHistory{_,_} where _ where _}}
  end::Union{Array{Float64,1}, Tuple{Array{Float64,1},IterativeSolvers.ConvergenceHistory{_,_} where _ where _}}

[mohamed82008]

I am using Julia v0.6.2 with IterativeSolvers v0.4.2+

[mohamed82008]

Same result on master.

[mohamed82008]

Changing keyword arguments to positional ones and making log a parameter passed as Val{log} fixes the type instabilities.

[ChrisRackauckas]

That's just a v0.6 issue that's fixed in v0.7. I wouldn't change the API for that.

[mohamed82008]

Cool! Closing the issue then. The above is a quick and dirty fix for v0.6 users to use on their machines if needed.