How to create matrices of Symbolic Variables in an earlier version of Symbolic toolbox

Hi,

Is there any way in which a command with similar functionality as X = sym('x',[2*N,1]); can be worked with an earlier version of Matlab where such commands are not supported..any answer in the right direction will be appreciated.

I currently work on an optimization problem of a throughput model (in commodities). The large number of related variables necessitates me to use symbolic toolbox to create matrices (or arrays) of symbolic vars..Unfortunately, the old version of Matlab is not supporting the command.

thanks,

Hari

Answer 1

[Alan Weiss]

This might not be as slick as the other answers, but it is in the documentation, and is easy to generalize.

Alan Weiss

MATLAB mathematical toolbox documentation

[Andrei Bobrov]

+1

Answer 2

[Azzi Abdelmalek]

N=10;
evalin('base',['y=sym([x1' sprintf(' ,x%d ',2:N) '])'])

Answer 3

[Andrei Bobrov]

2D symbolic array with size [7 x 5]:

m = 7; n = 5;
[ii,jj] = ndgrid(1:n,1:m);
v = sprintf('x%d%d,',[ii(:),jj(:)]');
X = reshape(sym(['[',v(1:end-1),']']),m,[]);

ADD after Alan Weiss's answer

m = 7; n = 5;
[ii,jj] = ndgrid(1:m,1:n);
s = arrayfun(@(x,y)sprintf('x%d_%d',x,y),ii,jj,'un',0);
X = sym(s);