Array indices must be positive integers or logical values.

Hi! I am getting this error and I do not understand why.

This is the line that is producin the error. However, all variables in this line have been defined successfully, and none of them are arrays. I do have the final loop, but it uses positive integers. Any thoughts?

M_max = -R1(distg2-distr1)+G1(distg2-distg1);
M_min = 0;
M_m = (M_max + M_min)/2;    % Median moment
M_a = (M_max - M_min)/2;    % Alternating moment
s_m = M_m*(d/2)/I;          % Sigma m
s_a = M_a*(d/2)/J;          % Sigma a
sigma_m = zeros(3);
sigma_a = zeros(3);

for (i = 1:3)
    sigma_m(i) = kt(i)*s_m;           % von mises equivalent median stress
    sigma_a(i) = kt(i)*s_m;          % von mises equivalent alternating stress
end

Answer 1

[Walter Roberson]

You forgot to put in the multiplication operator. MATLAB has no implied multiplication, not anywhere. A(B) is indexing or function invocation, never multiplication.

[Stephen23]

Does any (commonly used) programming language have implied multiplication?

[Walter Roberson]

In Maple, if a numeric constant appears before a non-numeric expression, then it will be multiplied, and non-numeric expressions separated by whitespace will be multiplied. So 3 x y is valid Maple but not x 3 y or 3 x 5 y