CODEWITHSUNDEEP
julia
Leonidas Souliotis
Leonidas Souliotis

Reputation: 105

MethodError: no method matching isless(::Symbol, ::Int64)

I am trying to build a Dirichlet Process Gibbs Sampler in Julia and represent each cluster as an object. I did the following:

using BayesianNonparametrics
using DataFrames
using Distances

type cluster
    m::Vector
    Sigma::LinAlg.Cholesky
    nu::Int
    kappa::Int
    nk::Int
  end

function logPredPdf(f::cluster,x::Array{Float64,1}):

  kappa <- f.kappa
  S <- f.Sigma
  mu <- f.m
  nu <- f.nu

  d <- size(x)[1]
  v = nu-d+1
  U = sqrt((1+1/kappa)/v) * LinAlg.lowrankdowndate!(S, sqrt(f.kappa)*mu)[:U]

  x = x - m
  Q = \(transpose(U),x)
  q= vecdot(Q,Q)
  o = -log(1+q/v)*((v+d)/2)
  c = lgamma((v+d)/2)-lgamma(v/2)-(d*log(v*pi)+2*sum(log(diag(U))))/2
  y = c + o

  return y
end

data = readtable("PCA_transformed_data_gt1000.csv",header= true);
data = delete!(data, :1);
n,d = size(data);

s = 6.6172
S0 = s*eye(d)
kappa_0 = 1
nu_0 = d
mu_0 = zeros(d)
S1 = LinAlg.cholfact(S0+kappa_0*(mu_0*mu_0'))

X= DataFrame(Matrix(data)');# transpose data Matrix
prior = cluster(mu_0, S1,nu_0, kappa_0, 0)

x = X[:,1]
kt = logPredPdf(prior,x)

When I run the lines inside the logPredPdf outside of the function it works perfectly! But if I try to run the above example, when it goes in the end, it gives me the following error:

MethodError: no method matching isless(::Symbol, ::Int64)
Closest candidates are:
  isless(!Matched::Char, ::Integer) at deprecated.jl:49
  isless(::Symbol, !Matched::Symbol) at strings/basic.jl:137
  isless(!Matched::DataArrays.NAtype, ::Any) at /Users/u1560476/.julia/v0.5/DataArrays/src/operators.jl:510
  ...
 in logPredPdf(::cluster, ::Array{Float64,1}) at Dirichlet_Process_Gibbs_Sampler.jl:33
 in include_string(::String, ::String) at loading.jl:441
 in include_string(::String, ::String, ::Int64) at eval.jl:30
 in include_string(::Module, ::String, ::String, ::Int64, ::Vararg{Int64,N}) at eval.jl:34
 in (::Atom.##53#56{String,Int64,String})() at eval.jl:50
 in withpath(::Atom.##53#56{String,Int64,String}, ::String) at utils.jl:30
 in withpath(::Function, ::String) at eval.jl:38
 in macro expansion at eval.jl:49 [inlined]
 in (::Atom.##52#55{Dict{String,Any}})() at task.jl:60

The types of "prior" and "x" are cluster and Array{Float64,1}, as the function asks for. Any ideas what I am missing here?

Upvotes: 1

Views: 6655

Answers (2)

mbauman
mbauman

Reputation: 31342

<- is not an operator in Julia. Use = for assignment in Julia. No package (or even macro) would ever allow you to write Julia code that contains a functional <- operator. x <- y always means x is less than -y:

julia> expand(:(x <- y))
:(x < -y)

julia> Meta.show_sexpr(ans)
(:call, :<, :x, (:call, :-, :y))

I imagine you happened to have those variables defined as you expected in your global workspace, but within that file it looks like kappa is bound to a Symbol instead.

Edit: You also must remove the : from function logPredPdf(f::cluster,x::Array{Float64,1}):. Function definitions (and blocks in general) do not use : in Julia.

Upvotes: 5

Leonidas Souliotis
Leonidas Souliotis

Reputation: 105

Changing all <- to = didn't fix the problem, but adding 

  let
     global k

after 

function logPredPdf(f::cluster,x::Array{Float64,1}):

seems to solve the problem! Still don't know why though!

Upvotes: 0

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