IF … Elif…Else flow

Question

I created a function with an if flow control, I am wondering a few things about it.

class Supplier(Process):

    def weeklySupply(self):
        global D1Vals
        xMeet = D1Vals[0]
        lead = 0
        capac = 150.0
        supply = 0
        if stocked.amount >= 15000:
            supply = 0
            yield put, self, stocked, supply
            S1Vals.append(0)
        elif supply >= capac:
            supply = capac
            yield put, self, stocked, supply
            S1Vals.append(capac)
        else:
            supply = random.triangular(.70 * xMeet , xMeet , xMeet * 1.05)
            yield put, self, stocked, supply
            print ('Week:'+'%6.0f:Supplied: %6.0f units. CurSupply = %6.0f' %
                   (now() + 1., supply, stocked.amount))
            yield hold, self, lead
            S1Vals.append(supply)
            del D1Vals[0]

What I though I coded was:

• If the amount in the stocked object was >= 15000, then the object generates zero supply or if a supply value was generated which was greater than a predefined 'capac' amount, then the supply value = 'capac'.

• If non of the above were true then the supply value was generated as a random distribution. When I get my output though, the supply value does exceed the 'capac' value of 150.

Have I misunderstood how to do the flow?

Answer 1

Do not mixup the if elif construct with some kind of or as you did in your question. The elif condition will only be evaluated if the if condition is False. I think, what you really want is:

if stocked.amount >= 15000:
    if supply >= capac:
        supply = capac
        yield put, self, stocked, supply
        S1Vals.append(capac)
     else:
        supply = 0
        yield put, self, stocked, supply
        S1Vals.append(0)
else:
    supply = random.triangular(.70 * xMeet , xMeet , xMeet * 1.05)
    ...

But this would only work, if supply is not initialised with 0 at the beginning of the function.

Answer 2

Seems to work a treat, and some nice things for me to think about. Only issue I can see is now my S1Vals list has stopped having the zero supply appended to the list. I can see this on my output graph and also when i do a len(S1Vals). The final code is with your suggestions is:

if stocked.amount >= 15000:
        if supply >= capac:
            supply = capac
            S1Vals.append(capac)
            yield put, self, stocked, supply
        else: 
            supply = 0.0
            yield put, self, stocked, supply
            S1Vals.append(supply)
    else:
        supply = min(capac, random.triangular(.70 * xMeet , xMeet , xMeet * 1.05))
        yield put, self, stocked, supply
        print ('Week:'+'%6.0f:Supplied: %6.0f units. CurSupply = %6.0f' %
               (now() + 1., supply, stocked.amount))
        yield hold, self, lead
        S1Vals.append(supply)
        del D1Vals[0]

To get here I used the flow suggestion above from MaxPower, also min(supply,capac), and declared a global supply. The last issue seems that supply = 0.0 never kicks in, but it should really?