Optimization with constraints matlab

[gfd43tg]

Homework Statement

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.

Homework Equations

The Attempt at a Solution

(a)

bMin = 0.001;
bMax = 0.2;
hMin = 0.001;
hMax = 0.2;
Pv = 1000;
Ph = 100;

(b)

N = 500;

(c)

bValues = linspace(bMin,bMax,N);
hValues = linspace(hMin,hMax,N);

(d)

B = repmat(bValues,N,1)';
H = repmat(hValues,N,1);

(e)

S1 = (6*Pv)./(B.*H.^2);

(f)

S2 = (6*Ph)./(B.^2.*H);

(g)

D1 = (4*Pv)./(2e11.*B.*H.^3);

(h)

D2 = (4*Ph)./(2e11.*B.^3.*H);

(i)

A = B.*H;

(j)

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).

[indexValidDesigns, I] = find((S1 < 1e8) & (S2 < 1e8) & (D1 < 0.001) & (D2 < .001));

 

[gfd43tg]

I just redid what I put in part (j)

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.