Can't Iterate on (::Task)

General Usage
1

i have a package built where i’m calling one function called prob with two methods inside a constructor called QRelaySampler and after i call it using QR=QRelaySampler([2 3;1 1],1 ,1, 0.5) then QR.prob(200) it shows me this following error:

ERROR: MethodError: no method matching iterate(::Task)
Closest candidates are:
  iterate(::Core.SimpleVector) at essentials.jl:604
  iterate(::Core.SimpleVector, ::Any) at essentials.jl:604
  iterate(::ExponentialBackOff) at error.jl:214

the same thing when i call it using the second method QR.prob(200,150,2)

**ERROR:** MethodError: objects of type Float64 are not callable

Stacktrace:

 [1] **(::getfield(QuantumRelay, Symbol("#prob#6")){Int64,Int64,Array{Float64,2},Array{Float64,2},getfield(QuantumRelay, Symbol("#setc#3")){Array{Float64,2},JuMP.Model},getfield(QuantumRelay, Symbol("#scan#4")){JuMP.Model,Int64,Array{Int64,1},Array{Int64,1},Array{Int64,1},Array{JuMP.Variable,1}},Float64})(** ::Int64, ::Int64, ::Int64 **)** at **/Users/midow/.julia/packages/QuantumRelay/aX3kK/src/QuantumRelay.jl:78**

 [2] top-level scope at **REPL[29]:1**

and this is a part of the code:

function prob(na)
		    @assert count(!iszero, ui2*na) == 0
		    b = T0*na
		    setc(-b)
		    total = 0.0
		    for x in Task(scan)
		        nab = vi2*x + b #the photon numbers for each item in the sum in the note (10)
		        total += prod([c.^complex(n)/factorial(n) for (c, n) in zip(coef, nab)])
		    end
		    return abs(total*omega)^2
		end

        #compute the probability of detection
        #q: the number of photons detectors report
        #na: the number of photons arrived at detector
        #mask: if there is no detector in this channel, mask=0
		function prob(q, na, mask)
		    q0 = round(Int, q.>0)
		    m0 = round(Int, mask)
		    return prod((q0 + (1-2q0).*pdet0(na)).^m0)
		end

the code generally for computing the probability for an ideal system for a detector and then for a realistic system.

you can also find the code in Github in this link :

2

I suspect your problem is:

for x in Task(scan)

That returns a Task, not a channel, did you mean:

for x in Channel(scan)

That will execute scan as a task and pass it a channel which is also returned so you can iterate on it.

1 Like
3

your idea should work except right now the code rises a BoundsError :
ERROR: BoundsError: attempt to access 0-element Array{JuMP.Variable,1} at index [1] and the error occurs in another file of the package :frowning_face::sweat:
:sob:
https://github.com/marouanehanhasse/Quantum_Relay/blob/master/src/scan.jl