How can I fix the error, or what does it mean "Subscript indices must either be real positive integers or logicals."?

Densityex = [ 0.974 0.938 0.948 0.932 0.893 0.865 0.863 0.844]; Tempex= [ 24 25 25 25.6 25.2 24.2 24.1 24.1]; alpha = 25*10^-6; Density = zeros(1:numel(Densityex)); for i =1:numel(Densityex) n = Densityex(i); for j = 1:numel(Tempex) N = Tempex(j); Density(n,N) = Densityex(n)*(1+ alpha(Tempex(N)-60)); end end

Answer 1

[Roger Stafford]

The error refers to the line

Density(n,N) = ...

because both n and N are being as indices in 'Density' but neither are positive integers, as all indices must be.