Need help with a nested for loop

I have

L = 28x1 vector

D = 28x1 vector

My equation is: V = L*((pi*((D+0.064).^2)/4)-(pi*D.^2)/4)

I have tried

for n = 1:length(D1)
    for m = 1:length(L1)
        TankVol(n,m) = L1(m,:)*((pi*((D1(n,:)+0.064).^2)/4)-(pi*D1(n,:).^2)/4);
    end
end

But it's not giving what I need

It's going through the loop too many times if that makes sense, I basically need a V value for each value in L and D.

Answer 1

[Image Analyst]

If there is a value of D1 for every value of L1 and vice versa, what about:

L1 = rand(28, 1); % 28x1 vector
D1 = rand(28, 1); % 28x1 vector
% My equation is: V = L*((pi*((D+0.064).^2)/4)-(pi*D.^2)/4)
for n = 1:length(D1)
    for m = 1:length(L1)
        TankVol(n,m) = L1(m)*((pi*((D1(n)+0.064).^2)/4)-(pi*D1(n).^2)/4);
    end
end
imshow(TankVol, []);

Or, if you want to take the nth element of D1 at the same time that you take the nth element of L1:

L1 = rand(28, 1); % 28x1 vector
D1 = rand(28, 1); % 28x1 vector
% My equation is: V = L*((pi*((D+0.064).^2)/4)-(pi*D.^2)/4)
TankVol = L1 .* ((pi*((D1+0.064) .^ 2)/4)-(pi*D1 .^ 2)/4);
plot(TankVol, 'b*-');
grid on;

[Joel Coburn]

Worked perfectly! Thanks so much

[Image Analyst]

Just curious - which version did you use?

Answer 2

[Murali Krishna]

In matlab u need not use loop to access each element. Try this

V = L.*((pi*((D+0.064).^2)/4)-(pi*D.^2)/4)

result will be stored in v as column matrix

Answer 3

[Walter Roberson]

 t = ((pi*((D+0.064).^2)/4)-(pi*D.^2)/4);
 V = bsxfun(@times, L, t.');