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D1 (Decision 1) 17 May 2013 Official Thread watch

1. Thanks guys! I'll write it in and cross it out
Good luck for tomorrow - major cramming is underway :/
2. No you just write the possibilities and if it's higher then you add them in. If you follow the algorithm perfectly then you should get exactly the same in the markscheme. Also does it matter in djikesta if you start at 1 or 0?
3. (Original post by niki135)

When you're doing Dijkstra's algorithm and you have, let's say, point G with a working value of 15. Then the second working value you do is bigger than 15, do you still write it in and cross it out? Or do you just leave it out completely?!

Thank you! x
I usually write it in a bracket
4. Hey guys, when drawing activity networks I know we should start from 0 but why have they started from 1 in the Jan 2009 Q3 paper?
5. (Original post by Fortitude)
Hey guys, when drawing activity networks I know we should start from 0 but why have they started from 1 in the Jan 2009 Q3 paper?
Exactly this??

In book, it's from zero, but from 1 in mark scheme. My teacher uses 1 as well.
6. (Original post by Vaner)
Exactly this??

In book, it's from zero, but from 1 in mark scheme. My teacher uses 1 as well.
I know right, it's specifically 0 in the book, I mean they've even called it the source node.
7. (Original post by Fortitude)
I know right, it's specifically 0 in the book, I mean they've even called it the source node.
I just checked, in the book they use 1 (looked at the Dijkstra examples), I've never seen the start being labelled as 0. It is however always 0 for the length.

Maybe this is where the confusion is

|*letter*|*label no.*|*shortest length*|

If the first/starting node is A then:

|A|1|0|

so just stick with 1 you guys !

EDIT: Just realized you guys may be talking about activity networks my bad
8. (Original post by posthumus)
I just checked, in the book they use 1 (looked at the Dijkstra examples), I've never seen the start being labelled as 0. It is however always 0 for the length.

Maybe this is where the confusion is

|*letter*|*label no.*|*shortest length*|

If the first/starting node is A then:

|A|1|0|

so just stick with 1 you guys !

EDIT: Just realized you guys may be talking about activity networks my bad
Well, you're not totally wrong; in past papers, the source node for activity networks is labelled 1, despite what the textbook says...
9. (Original post by posthumus)
I just checked, in the book they use 1 (looked at the Dijkstra examples), I've never seen the start being labelled as 0. It is however always 0 for the length.

Maybe this is where the confusion is

|*letter*|*label no.*|*shortest length*|

If the first/starting node is A then:

|A|1|0|

so just stick with 1 you guys !

EDIT: Just realized you guys may be talking about activity networks my bad
Ok I'm confused when you start an activity network, you start off with a node & that node is labelled 0 & then the line which connects from it is labelled A & this line connects to a node which is labelled 1.
10. Does anyone think scheduling is going to come up instead of a Gantt chart? I really hate them
11. (Original post by Fortitude)
Ok I'm confused when you start an activity network, you start off with a node & that node is labelled 0 & then the line which connects from it is labelled A & this line connects to a node which is labelled 1.
I don't even know why it even matters ??? I've never labelled them, I'd be surprised if we do get marked on our labeling.

(Original post by yugiohtheawesome)
Does anyone think scheduling is going to come up instead of a Gantt chart? I really hate them
I feel your pain, unfortunately scheduling is quite likely to come up... it's not too bad, just too time consuming ! So get as much practice as you can today, if you feel that's a weakness
12. (Original post by yugiohtheawesome)
Does anyone think scheduling is going to come up instead of a Gantt chart? I really hate them
Have no idea, it came up this time last year but it was after drawing a Gantt chart, I have no idea on how'd you draw a scheduling diagram straight from CPA.
13. (Original post by posthumus)
I don't even know why it even matters ??? I've never labelled them, I'd be surprised if we do get marked on our labeling.

I feel your pain, unfortunately scheduling is quite likely to come up... it's not too bad, just too time consuming ! So get as much practice as you can today, if you feel that's a weakness
I don't know, it probably doesn't matter because if it did, they would've mentioned it specifically in the mark scheme which they didn't so everything's ok

How would draw a scheduling diagram straight from a CPA w/o a Gantt chart?
14. someone please confirm when drawing the activity network we start from 0 yes or no?

THANK YOU
15. (Original post by otrivine)
someone please confirm when drawing the activity network we start from 0 yes or no?

THANK YOU
yes
16. (Original post by Fortitude)
I don't know, it probably doesn't matter because if it did, they would've mentioned it specifically in the mark scheme which they didn't so everything's ok

How would draw a scheduling diagram straight from a CPA w/o a Gantt chart?
By looking at your early/late time diagram (the one with nodes). It's actually pretty tricky and time consuming... as you would expect

It came up last year I think, I remember my brother telling me it threw everyone away ... and most people did gantt charts so hopefully it won't come up tomorrow since it already did last year.

EDIT: Oh really they had to draw both gantt chart & scheduling ? I think if they told us to do scheduling straight away, that would be pretty immoral ... it has been asked before though though drawing both charts is highly time consuming !

EDIT no.2 : Just checked they didn't ask to draw gantt chart .... only scheduling ? The good thing about that is, unlikely to come up again tomorrow
17. (Original post by otrivine)
someone please confirm when drawing the activity network we start from 0 yes or no?

THANK YOU
With activity networks, the leftmost box will always have [0|0] If it isn't, then you've messed up somewhere.
18. [COLOR="#FF0000" ]When it gives you an equation eg. 6x + 9y = P max, then does the graph cross at (0,6) and (9,0) ? is it always the coordinates of each other? [/COLOR] Thanks
19. (Original post by posthumus)
By looking at your early/late time diagram (the one with nodes). It's actually pretty tricky and time consuming... as you would expect

It came up last year I think, I remember my brother telling me it threw everyone away ... and most people did gantt charts so hopefully it won't come up tomorrow since it already did last year.
Hmmm, well here I am thinking there must be a quicker way I should seriously give up finding quicker ways to do D1 ...because so far there aren't any
20. (Original post by Coffeewaffee)
With activity networks, the leftmost box will always have [0|0] If it isn't, then you've messed up somewhere.
I don't think he's talking about the early/late time diagram

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