# MATLAB symbolic to double error

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Andrew on 7 Nov 2013
Commented: Walter Roberson on 7 Nov 2013
Hi, I am trying to run this code but there are errors. I don't know how to remove them. Here is code: This error comes when converting symbolic to double. Any help much appreciated.
clear all;
clc;
nel=4; % number of elements
totlength=10;
nne=3;
nnp=2*nel+1;
le=totlength/nel;
x=0:le:totlength;
element_nodes=[1:2:(nnp-2);2:2:(nnp-1);3:2:nnp]';
%element_nodes=[1:nel;2:nnp]';
B=[];
syms xlc
%Finding out B matrix
for i=1:1:nel
j=element_nodes(i,1)
B(i)=[(2*xlc-x(i+2)-x(j+1))/(2*le^2),(2*xlc-x(j+2)-x(i))/(-1*le^2),(2*xlc-x(j+1)-x(i))/(2*le^2)];
end
Any help or suggestions? Thanks.

Walter Roberson on 7 Nov 2013
Experiment with starting with
B = sym([]);
I think you are going to have trouble with your assignment to B(i) anyhow, as you appear to be attempting to assign a list of 3 elements into a single storage location.
Walter Roberson on 7 Nov 2013
B = sym([]);
And in the loop,
B(i,:) = [(2*xlc-x(i+2)-x(j+1))/(2*le^2),(2*xlc-x(j+2)-x(i))/(-1*le^2),(2*xlc-x(j+1)-x(i))/(2*le^2)];