flexsim engine shutdown

I have a model where I have a processor pulling from 7 different queues randomly. It all seems to work ok until I get an error message that says the FlexSim engine will shut down. I’ve uploaded my model so any help would be appreciated.


I guess I'm in position where I have an infinite sendmessage() situation. I guess I don't know a way around it though...

Gavin,
What is happening is your processor is sending a message to itself in the else statement of its OnMessage trigger, but it isn't changing any data. This means that if it ever gets into the else statement where it sends the message it will always go to the else statement and you are caught in an infinite loop.

As a side note, it is generally advisable to use senddelayedmessage() in 0 time instead of sendmessage(). Sendmessage() interrupts the code that is currently executing, whereas senddelayedmessage() will not be sent until that code has finished executing.

Looking at the code below:

int aa= uniform (1,7,1);
int b= content (inobject (current,aa));
if (b>0) openoutput (inobject (current,aa));
else sendmessage (current,current);


if I do enter the else condition then I will be changing the value of aa which should keep me out of an infinite loop?? I'm trying to randomly pull from 7 queues but only if there is product available. And it does crash when there is product avail.

You´ve built an infinite loop when content of all conected objects is 0.

for(int aa = 1; aa <= nrip(current); aa++)
{
int b = content(inobject(current,aa));
if(b>0) openoutput(inobject(current,aa));
}

should check all contents once!
But wouldn´t it be better to solve it with some logic in the inobjects?

I fall into an infinate loop before all of the object contents are 0. It works well for a while then crashes.



What I'm trying to do is pull from 7 separate queues randomly according to a uniform distribution. I need to keep pulling items as long as they exist in the queues and stop when the queues are empty. Any advice on how you would do it?

Gavin,

I was looking through the code again, and it looks like you are using uniform(1,7,1) when you should be using duniform(1,7,1) because it only returns discrete numbers whereas the uniform() returns all real numbers in the range.

Why don't you just write a Random Available Pull From Port option?

Attached is an example model showing this.

This code was taken from SendTo Random Available Port and modified to check the input ports instead of the output ports for pulling.

double arraysize = nrip(current);
doublearray openports = makearray(arraysize);
int nrofportsopen = 0;
for( int index = 1; index <= arraysize; index++)
{
	if(ipavailable(current,index))
	{
		nrofportsopen++;
		openports[ nrofportsopen ] = index;
	}
}
double returnvalue;
if(nrofportsopen > 0)
{
	int returnindex = duniform(1, nrofportsopen);
	returnvalue = openports[returnindex];
}
else
	returnvalue = 0;
return returnvalue;

The Pull Requirement you use is "Round Robin if available", this doesn´t do what you want?

I even found a solution, but it´s not quiet as simple as the others.
But maybe you see, what had been the trouble in your way.