Can you get truly random numbers from Dynamics NAV?

Were do you need to use such a generator?

I guess you could use some dll file that does only than, or even use Excel automation to generate a random number...

It depends on the version you are using.

You can look at the Excel Buffer Table to see how to Interact with excel. Otherwise you could create a .NET dll or COM interface depending on the version.

All in all, I think the topic is answered.
However, I am very curious in what business process a random number is needed.
Is it like a random discount? If you're lucky you'll receive a 100% discount?

Schrodinger's cat is long dead anyway, so why does it matter.

Get a dog instead. 8)

But if I open the box then the randomness is gone. My gut feeling is that after all these decades trapped in the box that the kitten has by now starved or suffocated

josephdewey wrote:

Pretty much all modern programming languages have the ability to generate real random numbers, and have gotten rid of the pseudo-random algorithms.

Which modern programming language are you talking about, which has built-in true random number generator? Just curious.

josephdewey wrote:

So, are Navision random numbers really random? I guess the answer really is: they're random enough.

I don't think so and I can tell you why.

Try to implement a simple Dice.

randomize(); //with a seed it's the same problem
message('The number is: %1 <- odd ?', random(6));

The first number is always an odd value (1, 3 or 5). :bug: :bug: :bug: :bug: :bug:

BTW: It's the same with all even values in the random function.
random(<even value>) returns an <odd value> at the first try.

Kind regards,
winfy

When trust is lost:
Park and Millers Minimal Standard Random Number Generator is simple, fast and in my opinion good enough for the most simulations in Navision.

Random2(VAR Seed : Integer;Number : Integer) : Integer

//......................................................................................................
//Name: Minimal Standard Random Number Generator (linear congruential generator)
//Source: Steve K. Park and Keith W. Miller "Random Number Generators: Good ones are hard to find", 1988
//Language: Navision C/AL (modified by winfy)
//Limits: only 32 Bit signed Integer. Generates Numbers from 1 to Parameter "Number"
//......................................................................................................

//Definitions
//a,m,q,r (Type Integer) 
//test, hi, lo (Type Integer)
//Seed (Typ Integer)

//Initialize the "good" Values
//the other Values are good alternatives too
a:= 16807;  //a:= 48271; //a:= 39373;
m:= 2147483647;
q:= 127773; //q:= 44488; //q:= 54542;
r:= 2836;   //r:= 3399   //r:= 1481;

//Generate the Random Number
hi := Seed DIV q;
lo := Seed MOD q;  
test := a * lo - r * hi; 

//Change to a positive range
IF test > 0 THEN Seed := test
  ELSE Seed := test + m;

//Result between 1 and the Parameter Number 
IF (Number > 0) THEN EXIT((Seed MOD Number) + 1)
  ELSE EXIT(1); //alternative EXIT(0) or Errormessage

Someone post it here before.
I think it's good enough to generate a Startseed with it.

Randomize2(VAR Seed : Integer)

//Generate a Seed with GUID values between 1 und 2.147.483.646.
//bigseed (Type BigInteger)
EVALUATE(bigseed, COPYSTR(DELCHR(CREATEGUID(),'=','{}-ABCDEF'),1,10));
Seed:= (bigseed MOD 2147483646) +1;

Maybe useful?

Literature: (Link)

Kind regards,
winfy

Yep, I did ti 3 years before to generate tracking no and till now no issue.
What I wrote was something like that.

WHILE NOT UniqueValue DO BEGIN
"Tracking No":=GenerateTrackingNo;
IF NOT CheckDuplicateTracking("Tracking No") THEN
UniqueValue := TRUE;
END;

Where GenerateTrackingNo was the function which was generating unique number with Random NAV Keyword and CheckDuplicateTracking was the function where I was just cross validating that the generated tracking number doesn't exist in the Database.

P.S - Till 6 month it was OK but after then what I experienced was system had started generating duplicate tracking numbers hence added to cross verify with the existing one in the DB.

My test passed when exposing a codeunit that returns a CREATEGUID generated value via SOAP web service and running 1000 rounds of 8 simultaneous requests to the web service. every round had 8 distinct values. either there's some kind of blocking going on in the way Navision handles SOAP web requests or the time window CREATEGUID uses is small enough that it's safe to use CREATEGUID like this. I imagine we wouldn't have people suggesting its use if it weren't. If anyone has more insight into how Navision handles web requests it would be interesting to me. I'm going to run it overnight with 2 threads per round and I'm confident it will pass. Thanks!

        static long y = 0; // threads finished count
        static long x = Environment.ProcessorCount * 1; // number of simultanious requests
        static ManualResetEvent done = new ManualResetEvent(false); // detect round finish
        static ManualResetEvent go = new ManualResetEvent(false); // synchronize request start times
        static ConcurrentBag<int> results = new ConcurrentBag<int>();
        static Test2.test2 p = new Test2.test2(); // navision codeunit via SOAP web service
        private static void work(object r)
        {
            var ready = (ManualResetEvent)r;
            ready.Set();
            go.WaitOne();
            results.Add(p.GetRand2());
            if (Interlocked.Increment(ref y) == x)
                done.Set();
        }
        static void Main(string[] args)
        {
            p.Credentials = new NetworkCredential("***********", "**********");
            for (int round = 0; round < 1000; round++) {
                for (int i = 0; i < x; i++)
                {
                    ManualResetEvent ready = new ManualResetEvent(false);
                    Thread g = new Thread(new ParameterizedThreadStart(work));
                    g.Start(ready);
                    ready.WaitOne();
                }
                go.Set();
                done.WaitOne();
                var p = results.Distinct();
                if (p.Count() != results.Count) throw new Exception("Test: FAIL");
                Console.Write('.');
                go.Reset();
                done.Reset();
                y = 0;
                results = new ConcurrentBag<int>();
            }
            Console.WriteLine("Test: PASS");
            Console.ReadKey();
        }

Even serialized, if the requests all construct instances of a run-of-the-mill PRNG within the same window of time they will generate the same PRN sets. This depends on the granularity of the clock being used to seed the PRNG. .NET Random default constructor seeds itself with a 1 millisecond window, which is offensively huge and broken.

CREATEGUID is probably calling .NET Guid.NewGuid so I looked up Microsoft's explanation of what's happening under that hood.

Remarks
This is a convenient static method that you can call to get a new Guid. The method wraps a call to the Windows CoCreateGuid function. The returned Guid is guaranteed to not equal Guid.Empty.

Remarks
The CoCreateGuid function calls the RPC function UuidCreate, which creates a GUID, a globally unique 128-bit integer. Use CoCreateGuid when you need an absolutely unique number that you will use as a persistent identifier in a distributed environment.To a very high degree of certainty, this function returns a unique value – no other invocation, on the same or any other system (networked or not), should return the same value.

CREATEGUID is practically immune if it's using this, which is very good.