Do you Know algorism ESGP

Hi all

I have trouble with problem

Min f1(x) = 0.225x1 + 2.2x2 + 0.8x3 + 0.1x4 + 0.05x5 + 0.26x6

Min f2(x) = 10x1 + 20x2 + 120x3

Min f3(x) = 24x1 + 27x2 + 15x4 + 1.1x5 + 52x6

Subject to:

720x1 + 107x2 + 7080x3 + 134x5 + 1000x6 > 5000

0.2x1 + 10.1x2 + 13.2x3 + 0.75x4 + 0.15x5 + 1.2x6 > 12.5

344x1 + 1460x2 + 1040x3 +75x4 + 17.4x5 +240x6 > 2500

18x1 + 151x2 + 78x3 + 2.5x4 + 0.2x5 + 4x6 > 63

x1 < 6

x2 < 1

x3 < 0.25

x4 < 10

x5 < 10

x6 < 4

I dont now the algorism to solve this problem. anyone to know the algorism to solve? please help me to solve the problem

Thanks all

[722 byte] By [tranquocnama] at [2007-9-28 19:04:34]
# 1
Looks like linear programming, although as you explain it you seem to be trying to simultaneously minimise three cost functions. Google up "Simplex algorithm"
YATArchivista at 2007-7-12 17:27:10 > top of Java-index,Other Topics,Algorithms...
# 2

You have a multi objective LP to solve...

One way to to create a new function g(x) = w1*f1(x)+w2*f2(x)+w3*f3(x)

and Min g(x)...

here w1, w2, w3 are weights or relative importance of each objective.

Alternately, you can look up some literature on Goal Programming...

Sandie

sandie348a at 2007-7-12 17:27:10 > top of Java-index,Other Topics,Algorithms...
# 3
Thank to reply. But I can't to solve it. Do you know the documents or web page?
tranquocnama at 2007-7-12 17:27:10 > top of Java-index,Other Topics,Algorithms...
# 4
What exactly are you trying to solve ?
sandie348a at 2007-7-12 17:27:10 > top of Java-index,Other Topics,Algorithms...
# 5

Hi sandie384

I real want to find x1,x2,x3,x4,x5,x6... satisfy the F1(x),f2(x)..and the subjects.

This is mutiple objectives linear programming problem . I hear some name of the algorism (e.g Efficient Solution Via Goal Programming (ESGP), Linear goal Programming (LGP)), but I have not the algorism to solve this problems. I realy want solve this problems, it urgent. If you know the problems, please help me to solve it.

Thanks.

tranquocnama at 2007-7-12 17:27:10 > top of Java-index,Other Topics,Algorithms...
# 6

I would approach the problem as follows...

1. Solve 3 LPs for each of the objective functions independently. Let the Optimal values of the objective function be F1*, F2*, F3* respectively. this is simple enough, just do a simplex 3 times!

2. Now to set up the Goal Programming problem

Let D1 = F1(x) - F1*

D2 = F2(x) - F2*

D3 = F3(x) - F3*

3. Solve the new LP

min D1 + D2 + D3

Subject to:

720x1 + 107x2 + 7080x3 + 134x5 + 1000x6 > 5000

0.2x1 + 10.1x2 + 13.2x3 + 0.75x4 + 0.15x5 + 1.2x6 > 12.5

344x1 + 1460x2 + 1040x3 +75x4 + 17.4x5 +240x6 > 2500

18x1 + 151x2 + 78x3 + 2.5x4 + 0.2x5 + 4x6 > 63

x1 < 6

x2 < 1

x3 < 0.25

x4 < 10

x5 < 10

x6 < 4

Essentially we are trying to minimize the total deviation from the individual optima...

This should give you a pretty good solution...

You can also play arond with this problem by saying

Min D1/F1* + D2/F2* + D3/F3* .... To allow for relative importance between the 3 objectives you listed.

Would this work?

S

sandie348a at 2007-7-12 17:27:10 > top of Java-index,Other Topics,Algorithms...
# 7
Check out some mathematical package like Mathematica, Meaple or Matlab.
MsTinglea at 2007-7-12 17:27:10 > top of Java-index,Other Topics,Algorithms...
# 8
I should be Maple and here's a link to Mathematica, http://www.wolfram.com
MsTinglea at 2007-7-12 17:27:10 > top of Java-index,Other Topics,Algorithms...