Aah simplex, it just makes you want to cry tbh i just practiced simplex a lot and i'm fairly confident in it now, i just make sure to double check all my answers as soon as i get to the row operations bit, like most of D2 i find that you are more likely to lose marks from wrong calculation than by not knowing what you're doing
I'm just getting lots of practice (doing all the exercises in the book) and trying to keep the algorithms fresh in my head, so the exam should be okay i hope
Hey, it's nice to find other people doing D2; I'm sitting this exam as well. Is your school making you guys sit this exam or are you guys self-teaching it?
Hey, it's nice to find other people doing D2; I'm sitting this exam as well. Is your school making you guys sit this exam or are you guys self-teaching it?
Nah D2 is part of my further maths A2 so my whole class is doing it i personally love it but literally the rest of the class hates it
How do you know the inequality signs for this? I know which 2 are best upper/lower bound but why the less than or equal to inequality sign for upper bound and not lower bound?????
How do you know the inequality signs for this? I know which 2 are best upper/lower bound but why the less than or equal to inequality sign for upper bound and not lower bound?????
The thing to understand is that when you calculated the upper bound you calculated and actual route so it is a feasible solution
The method to find the lower bound simply gives a value for the lower bound, it doesn't actually give a feasible solution, if you draw out the network you got after adding back C in part (e) of the question then you'll notice that it doesn't actually give you a feasible route, therefore the inequality sign is just a more than sign
N.B If you delete a vertex and then add it back in and you get a tour, then this is the optimal solution ... but that doesn't usually happen
The thing to understand is that when you calculated the upper bound you calculated and actual route so it is a feasible solution
The method to find the lower bound simply gives a value for the lower bound, it doesn't actually give a feasible solution, if you draw out the network you got after adding back C in part (e) of the question then you'll notice that it doesn't actually give you a feasible route, therefore the inequality sign is just a more than sign
N.B If you delete a vertex and then add it back in and you get a tour, then this is the optimal solution ... but that doesn't usually happen
Ahh that makes sense, I understand, thank you , how did you know this?
How do i find the minimum cut on this diagram (capacitated) ???
Afaik the minimum cut is one that goes through only saturated arcs (conditions are p193 in the textbook). Therefore you need the flows to see which cut is a minimum
Afaik the minimum cut is one that goes through only saturated arcs (conditions are p193 in the textbook). Therefore you need the flows to see which cut is a minimum
It can also go through empty arcs as well but these would not contribute to the value of the min cut (as they are 'out of cut').