Looping over a vector with non-integer values
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I'm trying to loop through each element of the vector 'N' but it keeps giving me back the 'attempting to access; index must be a positive integer or logical.' Is there a way I can do this without having to do each of them separately?
N = [15.66 9.27 6.72 4.84 4.1 3.4];
km_factors = zeros(size(N));
r = (616/2)/1000;
m = 1140;
vh = 1.999;
for i = N
x(i) = (0.3*i)/r;
z = m/vh;
km_factors = (2.73e-02*(x(i)))+(9.85e-04*(x(i)^2))-(5.71e-05*(z)) ...
+(8.22e-08*(z^2))-(2.87e-05*(x(i)*z));
end
disp(km_factors);
2 个评论
per isakson
2015-2-4
"do each of them separately?"   What do you mean? Do what separately?
Levi Autrey
2015-2-4
采纳的回答
Star Strider
2015-2-4
I don’t know exactly what you want, but one solution is to set the for loop index to go from 1 to the length of ‘N’. I substituted ‘N(i)’ for ‘i’ in the ‘x’ assignment, and subscripted ‘km_factors’. It works. Check to be certain it calculates what you want:
N = [15.66 9.27 6.72 4.84 4.1 3.4];
km_factors = zeros(size(N));
r = (616/2)/1000;
m = 1140;
vh = 1.999;
for i = 1:length(N)
x(i) = (0.3*N(i))/r;
z = m/vh;
km_factors(i) = (2.73e-02*(x(i)))+(9.85e-04*(x(i)^2))-(5.71e-05*(z))+(8.22e-08*(z^2))-(2.87e-05*(x(i)*z));
end
Note that it’s generally not a good idea to use ‘i’ and ‘j’ as variables, including loop counters, because MATLAB uses those for its imaginary operators. Not using them as variables avoids confusion.
2 个评论
Levi Autrey
2015-2-4
Star Strider
2015-2-4
My pleasure!
I remember encountering the same problem when I was learning MATLAB.
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