How to substitute a vector symbolic variable with the values of a vector?

 x = sym('x',[1 2]).';
Q = [1 0;0 1]
f = x.'*Q*x;
xo = ones(2,1)
fo = (subs(f,{x(1),x(2)},{xo(1),xo(2)}))

x is a symbolic vector of dimension 50. I want to substitute 50 values in xo into each of x1,x2,....x50 in x.

Thanks a lot!

Answer 1

[madhan ravi]

Your code works fine, you can substitute the same way using curly braces. What problem are you facing ?, everything seems to be fine in your code.

subs(f, x, xo) %edited after sir Walter’s comment.

[Vishnu Narayan Vipin]

In this way, I have to type in 50 separate curly braces, if dimension of x is 50. If the dimension scales up, its difficult to type in individual elements right? I want to assign whole of xo(dimesnion 50) to symbolic vector x(dimension 50). Thank you for replying!!

[madhan ravi]

I think if you look at the documentation of subs() it’s only used for scalar values so you would have to substitute each values separately.

[Walter Roberson]

 subs(f, x, xo)

In the case of vector of variables and vector of values the same size, corresponding substitute is done. The {} notation would be needed if at least one of the substitutions was not a scalar.

[madhan ravi]

Thank you @sir Walter