isreplicated

The nexuslua function isreplicated is pivotal for determining the instantiation status of a given agent. It assesses if the currently executing agent instance is the primary (first) instance or if it's an auxiliary instance that was automatically spun up to handle increased workload. Recognizing the distinction is crucial, particularly for actions that should be performed just once, like invoking addmessage or dispatching initial messages.

Example

local nRequests = 0
local nCheckedPrimes = 0
local count = 0
 
function CountPrime(parameters)
    nCheckedPrimes = nCheckedPrimes + 1
 
    if parameters.isPrime then
        count = count + 1
    end
    
    if (nCheckedPrimes == nRequests) then
        print("Checked ", nCheckedPrimes, " numbers, found ", count, " primes.")
    end
end
 
function RequestPrimes(parameters)
    print("Analyzing prime numbers between ", parameters.n1, " and ", parameters.n2)
 
    for i=parameters.n1,parameters.n2,2 do
        send("numbers", "IsPrime", {number=i, threads=16, reply_to={agent="main", message="CountPrime"}})
        nRequests = nRequests + 1
    end
end
 
if not isreplicated() then
    local numbersCode=[==[
        function IsPrime(parameters)
            local number = tonumber(parameters.number)
            q=math.sqrt(number)
            found=true
            for k=3,q,2 do
                d = number/k
                di = math.floor(d)
                if d==di then
                    found=false
                    break
                end
            end
 
            return {isPrime=found}
        end
 
        addmessage("IsPrime")
    ]==]
 
    addagent("numbers", numbersCode) -- an alternative approach would be to place the above code into numbers.lua and invoke addagent("numbers", readfile("numbers.lua"))
    addmessage("CountPrime")
    addmessage("RequestPrimes")
 
    send("main", "RequestPrimes", {n1=100000000001,
                                   n2=100000100001})
end

Key Insights

The isreplicated function is intended to be used as a gatekeeper, ensuring certain instructions are executed solely by the primary agent instance, and not by any replicated instances. This distinction avoids redundancy, maintains efficiency, and ensures that specific operations, especially those related to initialization or setup, are executed only once.

See also

• addagent
• ddmessage
• send