Stop Iteration Error

[quest]

Hello,

here is my class:

class inportProp:
    
    def __init__(self, t0, tM, incoming, phys, clinkdt, otherport=None, name=''):
        self.DEBUG=True 
        self.lastt=t0
        self.tM=tM
        if self.tM == 0: 
            def updateqmem(t):
                pass 
        else :
            def updateqmem(t):
                 
                perase=-expm1(-(t-self.lastt)/self.tM)
                for i,q in enumerate(self.physqueue): 
                    if random()<perase:
                        q.lost() 
                        
                        del self.physqueue[i]
        self.updateqmem=updateqmem
        self.incoming=incoming
        self.phys=phys
        self.physqueue=[]
        self.dataqueue=[]
        self.clinkdt=clinkdt
        self.otherport=otherport
        if otherport != None:
            if otherport.otherport==None :
                otherport.otherport=self
                otherport.clinkdt=clinkdt
            else: raise ValueError(f"{otherport} already ok") 
            self.nextitemin()
            self.otherport.nextitemin()
        self.name=name
 
    def __next__(self):
        while True:
            if len(self.dataqueue)==0:
                self.otherport.nextitemin() 
            while self.lastt < self.dataqueue[0][0]: 
                self.nextitemin()
            td, cdata = self.dataqueue.pop(0)
            self.updateqmem(td)
            self.lastt=td
            while len(self.physqueue)>0 and self.physqueue[0][1].idt<cdata:
                self.physqueue.pop(0) 
            if  len(self.physqueue)>0 and self.physqueue[0][1].idt==cdata:
                tq, qb = self.physqueue.pop(0)
                return [td, qb]
         
    def nextitemin(self):
        tq, q = next(self.incoming)
        self.updateqmem(tq)
        if self.phys==0 or len(self.physqueue)<=self.phys:
            self.physqueue.append([tq, q]) 
        self.lastt=tq
        self.otherport.dataqueue.append([tq+self.clinkdt, q.idt])
        if self.DEBUG :
            print(f'{self.name}.nextitemin')
            self.showstate()
 
    def showstate(self):
        print(f'{self.name}, t={self.lastt}')
        print(f'Physqueue:{self.physqueue}')
        print(f'Dataqueue:{self.dataqueue}')

here the code that I used for testing:

src=source(rate=.5,eta=1)
print("PAIRS************************",src)
Abits=link(eta=.8, deltat=1.5, inputs=src.portA)
Bbits=link(eta=0.7, deltat=3.2, inputs=src.portB)
for x in Abits:
    print(f"{x} —> {x[1].idt}, {x[1].QEO.state}")
    print('=')
    print(f'fifos: A {len(src.Afifo)}, B {len(src.Bfifo)}')
print(10*"=")
for x in Bbits:
    print(f"{x} —> {x[1].idt}, {x[1].QEO.state}")
    print(f'fifos: A {len(src.Afifo)}, B {len(src.Bfifo)}')


inport1=inportProp(t0=0, tM=0, incoming=Abits, phys=10, clinkdt=4.7, name='A')
inport2=inportProp(t0=0, tM=0, incoming=Bbits, phys=10, clinkdt=4.7, otherport=inport1, name='B')

And I am getting this error:

Error:
...
---------------------------------------------------------------------------
StopIteration                             Traceback (most recent call last)
<ipython-input-128-6a60e37ecdbf> in <module>
     14 
     15 inport1=inportProp(t0=0, tM=200.0, inbits=Abits, phys=10, clinkdt=4.7,name='A')
---> 16 inport2=inportProp(t0=0, tM=200.0, inbits=Bbits, phys=10, clinkdt=4.7, otherport=Ainport, name='B')#otherport=Ainport,
     17 
     18 

<ipython-input-127-5d7a8dbcb4e0> in __init__(self, t0, tM, inbits, phys, clinkdt, otherport, name)
     42                 otherport.clinkdt=clinkdt
     43             else: raise ValueError(f"{otherport} already connected to someone else")
---> 44             self.nextitemin()
     45             self.otherport.nextitemin()
     46 

<ipython-input-127-5d7a8dbcb4e0> in nextitemin(self)
     64 
     65     def nextitemin(self):
---> 66         tq, q = next(self.inbits)
     67         self.updateqmem(tq)
     68         if self.phys==0 or len(self.physqueue)<=self.physqueuesize:

StopIteration: 

However if I do not write this part:

for x in Abits:
    print(f"{x} —> {x[1].idt}, {x[1].QEO.state}")
    print('=')
    print(f'fifos: A {len(src.Afifo)}, B {len(src.Bfifo)}')
print(10*"=")
for x in Bbits:
    print(f"{x} —> {x[1].idt}, {x[1].QEO.state}")
    print(f'fifos: A {len(src.Afifo)}, B {len(src.Bfifo)}')

code is working..
Probably some timing/ memory problem and I need skip stop Iteration part and maybe I need to write a function for that but I do not know how to do

Any helps...
Bests

[Gribouillis]

The StopIteration exception does not necessarily mean an error. It is the way Python indicates the end of a sequence when you call the next() function. It may simply mean that there are no more items in the sequence.

[quest]

The StopIteration exception does not necessarily mean an error. It is the way Python indicates the end of a sequence when you call the next() function. It may simply mean that there are no more items in the sequence.

how can I pass it? because really I do not want to see it. It appears the line of

tq, q = next(self.incoming)

then it is going next function and then stop iteration...
How to manage with that because I change nothing in the code and sometimes it is perfectly fine but sometimes "StopItreration" and ot is very annoying since I change nothing...

[Gribouillis]

If you want to pass it you need to say what the program has to do when there are no more items in the sequence

try:
    tq, q = next(self.incoming)
except StopIteration:
    # No more items in self.incoming --> what to do here?

You can also catch the exception at higher level in the calling stack.

[quest]

If you want to pass it you need to say what the program has to do when there are no more items in the sequence

try:
    tq, q = next(self.incoming)
except StopIteration:
    # No more items in self.incoming --> what to do here?

You can also catch the exception at higher level in the calling stack.

this time I am in a never endless loop...

I will think and try something and will let you know..
Thanks