Engineering Optimization: Theory and Practice, Fourth Edition

(Martin Jones) #1
Problems 489

Determine whether the solution

X=




√^0
√^2
2




is optimum by finding the values of the Lagrange multipliers.

7.43 Determine whether the solution


X=




√^0
√^2
2




is optimum for the problem considered in Example 7.8 using a perturbation method with
xi= 0 .001,i= 1 , 2 ,3.

7.44 The following results are obtained during the minimization of


f (X)= 9 − 8 x 1 − 6 x 2 − 4 x 3 + 2 x 12 + 2 x 22 +x^23 + 2 x 1 x 2 + 2 x 1 x 3
subject to
x 1 +x 2 + 2 x 3 ≤ 3
xi≥ 0 , i= 1 , 2 , 3
using the interior penalty function method:

Starting point for
minimization of Unconstrained minimum
Value ofri φ (X, ri) ofφ (X, ri)=X∗i f (X∗i)=fi∗


1





0. 1
0. 1
0. 1







0. 8884
0. 7188
0. 7260




0.7072

0.01





0. 8884
0. 7188
0. 7260







1. 3313
0. 7539
0. 3710



 0.1564

0.0001





1. 3313
0. 7539
0. 3710







1. 3478
0. 7720
0. 4293




0.1158

Use an extrapolation technique to predict the optimum solution of the-problem using the
following relations:
(a) X(r) =A 0 +rA 1 ;f (r)=a 0 +ra 1
(b) X(r) =A 0 +r^1 /^2 A 1 ;f (r)=a 0 +r^1 /^2 a 1
Compare your results with the exact solution

X∗=






12
9
7
9
4
9






, fmin=^19
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