4) LP Cpa Minimum Project Time (rather Than Max Length)

Question 1

If it’s says complete in the minimum PROJECT TIME, now actually a Network

What becomes the objective function thus

Answer 1

MINIMISE T

Question 2

Why minimise T or whatever source is?
How ti work out the end value if not explicit?

Answer 2

Because the end vertex will have the highest value basicslly. So you want to minise this

2) if not explicit what the end vertex is, acc DO CPA TO FIGURE IT OUT

Question 3

Athen what are the cinstraints about?

Answer 3

Cinstraints are to do with how the task must be a minimum time before it can START

Question 4

So how to find all the constraints

Answer 4

1) this time look at ALL THE VERTICIS
- start at first non zero one makes sense in the flow. See the weight of it. If the weight is 5, it means it must wait ATLEAST 5 before it can start

Thus B>= to 5
2) look at next point in the flow. A depends on B and the weight is 13
- thus it must be B + 13 hours before it can start
So A>= B+ 13
- BUT LOOK AT ALL VALUES , not only must it wait for B, it must also furiously the time taken to go directly to it too!
Thus make sure to INCLUDE ALL PATHS GOING INTO EACH VERTEX AND YOULL BE FIND

Continue this on

Question 5

HOW TO WRITE THE CINSTRAINRS PROPERLY (STANDARD FORM)

Answer 5

They might ask you a q why won’t program understand this

This is because currently not standard form

Standard form is attests variables on the left side!, so bring them all to the left!!

Question 6

Summary

Answer 6

1) maximise end vertex
2) subject to
- all routes into each vertex, write down the minimum start time
- if it’s coming off a letter, can write a letter!
- expect multiple for a node don’t worry

4) write in STANDARD FORM, all in the left (all variables on the left)

Question 7

In retrospect how easy is it?

Answer 7

Just look every path going into a vertex and show how that variable >= letter + number, unless starts at 0!