Trying to create a matrix by nesting a for loop in another for loop

I am trying to create a nx9 matrix by nesting a for loop in another for loop, where n is the number of iterations of the first for loop, and 9 is the number of iterations in the nested for loop. Specifically, I am iterating through different values for the NTU of a heat exchanger in the first loop, and the nested loop iterates through 9 different surface areas (A) from actual heat exchangers. The overall heat transfer coefficient is calculated for each heat exchanger for each different NTU. Here is what I have so far

i = 0;

for NTU = 2.5:0.1:3.5

i = i + 1;

eff(i) = effectiveness(NTU, c, 'One Shell Pass');

Q(i) = eff(i)*Qmax; %kW

T5(i) = Q(i)/Cmin + T4;

T14(i) = T13 - Q(i)/Cmax;

NTU_i(i) = NTU;

%Finding the overall transfer coefficient

for j = 1:9

U(j) = ((NTU*Cmin)/A(j));

end

end

Answer 1

[Sindar]

No need for loops, except if effectiveness doesn't accept arrays

% nx1
NTU = (2.5:0.1:3.5).';
for i=1:length(NTU)
    eff(i) = effectiveness(NTU(i), c, 'One Shell Pass');
end
Q = eff*Qmax; %kW
T5 = Q./Cmin + T4;
T14 = T13 - Q./Cmax;

% make sure A is the right shape
if isequal(size(A),[1 9])
elseif isequal(size(A),[9 1])
    A = A.';
else
    error('A is not the expected size: 1x9')
end
%Finding the overall transfer coefficient 
% elementwise division will expand nx1 NTU / 1x9 A into nx9 U
U = (NTU.*Cmin)./A;

[Michael Costa]

Effectiveness will take an array. This worked great. Thanks for the help!