# Optimization with constraints matlab

1. Jun 17, 2014

### Maylis

1. The problem statement, all variables and given/known data
Just a heads up, this is a problem with parts (a) - (o). I am working on (k). I am working on problem 5 in the attached PDF. I will show my code for the other parts. We were told to use N = 5 while writing the code for debugging and testing, but run N = 500 for the real assignment. Either way, it doesn't make a difference right now because I don't know the synthax for finding indices in arrays for a single index.

2. Relevant equations

3. The attempt at a solution
(a)
Code (Text):
bMin = 0.001;
bMax = 0.2;
hMin = 0.001;
hMax = 0.2;
Pv = 1000;
Ph = 100;

(b)
Code (Text):
N = 500;
(c)
Code (Text):
bValues = linspace(bMin,bMax,N);
hValues = linspace(hMin,hMax,N);
(d)
Code (Text):
B = repmat(bValues,N,1)';
H = repmat(hValues,N,1);
(e)
Code (Text):
S1 = (6*Pv)./(B.*H.^2);
(f)
Code (Text):
S2 = (6*Ph)./(B.^2.*H);
(g)
Code (Text):
D1 = (4*Pv)./(2e11.*B.*H.^3);
(h)
Code (Text):
D2 = (4*Ph)./(2e11.*B.^3.*H);
(i)
Code (Text):
A = B.*H;
(j)
Code (Text):
constraints = find((S1 < 1e8) & (S2 < 1e8) & (D1 < 0.001) & (D2 < .001));
nValidDesigns = numel(constraints);
(k)
This is where I am now stuck. I'm not sure what command I can use to find the single index of the valid designs from part (j).
Code (Text):
[indexValidDesigns, I] = find((S1 < 1e8) & (S2 < 1e8) & (D1 < 0.001) & (D2 < .001));

#### Attached Files:

• ###### REL 5.pdf
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Views:
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2. Jun 17, 2014

### Maylis

I just redid what I put in part (j)

Code (Text):
indexValidDesigns = find((S1 < 1e8) & (S2 < 1e8) & (D1 < 0.001) & (D2 < .001));
And the autograder gave said its right. Kind of dumb that part (k) is just the same thing as part(j), no??

I will put any more questions pertaining to this problem in this thread. Thanks.