Syms function no longer works in a for loop which stores data

x= NaN(2,1);
syms F q L;
for i = 1:2
    for j = 1:2
       K(i,j) =  F*(L^(i+j+1))*((((i+1)*(j+1))/(i+j+1))+ ((i*j)/(i+j-1))) - (((2*i*j)+i+j)/(i+j)); % K matrix for the second iteration
       x(i,1) = q*(L^(i+2))*((1/(i+3)) - (1/(i+2))); % F vector for the second iteration 
    end
end
% Solving of the second linear equation of form Kc+F=0 to obtain {c2}
c2 = linsolve(K,-x);

I am getting an error saying it cant convert from sym to double whenever I stry to store K in a matrix and F in its vector. How can this be fixed?

Cheers

Answer 1

[Steven Lord]

If you try to do something like the following:

%{
syms x
F = 0;
F(2) = x;
%}

What numeric value should be stored in F(2) after that code runs? The answer is that x is symbolic and cannot be converted into a numeric value so this will throw an error. If you want to store symbolic data into an array preallocate that array to be a symbolic array from the start.

syms x
F = sym(0);
F(2) = x

F = 

G = sym(zeros(1, 10));
for k = 1:10
    G(k) = x.^k;
end
G

G =