How to evaluate sym using certain known multiple values?

I have a 2*3 sym (named "A") as follows:

[                                                                       1,                                                                                                                                                                                                                                                                   0,                                                                                                                                                                                                                                                                   0]
[-1/(2*(x1/(x2^2 - 10*cos(4*x3*pi) - 10*cos(4*x2*pi) + x3^2 + 21))^(1/2)), (x1*(2*x2 + 40*pi*sin(4*pi*x2)))/(2*(x1/(x2^2 - 10*cos(4*x3*pi) - 10*cos(4*x2*pi) + x3^2 + 21))^(1/2)*(x2^2 - 10*cos(4*pi*x3) - 10*cos(4*pi*x2) + x3^2 + 21)) - (2*x2 + 40*pi*sin(4*pi*x2))*((x1/(x2^2 - 10*cos(4*pi*x3) - 10*cos(4*pi*x2) + x3^2 + 21))^(1/2) - 1), (x1*(2*x3 + 40*pi*sin(4*pi*x3)))/(2*(x1/(x2^2 - 10*cos(4*x3*pi) - 10*cos(4*x2*pi) + x3^2 + 21))^(1/2)*(x2^2 - 10*cos(4*pi*x3) - 10*cos(4*pi*x2) + x3^2 + 21)) - (2*x3 + 40*pi*sin(4*pi*x3))*((x1/(x2^2 - 10*cos(4*pi*x3) - 10*cos(4*pi*x2) + x3^2 + 21))^(1/2) - 1)]

I want to evaluate this 2*3 sym at -

X=[0.394876, 0.963263, 0.173956]

where

x1=X(1);
x2=X(2);
x3=X(3);

How can I do this?

Note, I tried matlabFunction command. This causes certain problems in some certain scenarios. I do not want to use matlabFunction command.

Answer 1

[Rounak Saha Niloy]

double(subs(A, [x1, x2, x3], X));

Could sort it out. The above code evaluates the sym at X.

Answer 2

[John D'Errico]

Easy peasy, though using matlabFunction here is not my recommendation.

syms('x',[1,3])

So x is a vector, with elements [x1,x2,x3].

A = [[                                                                       1,                                                                                                                                                                                                                                                                   0,                                                                                                                                                                                                                                                                   0]
[-1/(2*(x1/(x2^2 - 10*cos(4*x3*pi) - 10*cos(4*x2*pi) + x3^2 + 21))^(1/2)), (x1*(2*x2 + 40*pi*sin(4*pi*x2)))/(2*(x1/(x2^2 - 10*cos(4*x3*pi) - 10*cos(4*x2*pi) + x3^2 + 21))^(1/2)*(x2^2 - 10*cos(4*pi*x3) - 10*cos(4*pi*x2) + x3^2 + 21)) - (2*x2 + 40*pi*sin(4*pi*x2))*((x1/(x2^2 - 10*cos(4*pi*x3) - 10*cos(4*pi*x2) + x3^2 + 21))^(1/2) - 1), (x1*(2*x3 + 40*pi*sin(4*pi*x3)))/(2*(x1/(x2^2 - 10*cos(4*x3*pi) - 10*cos(4*x2*pi) + x3^2 + 21))^(1/2)*(x2^2 - 10*cos(4*pi*x3) - 10*cos(4*pi*x2) + x3^2 + 21)) - (2*x3 + 40*pi*sin(4*pi*x3))*((x1/(x2^2 - 10*cos(4*pi*x3) - 10*cos(4*pi*x2) + x3^2 + 21))^(1/2) - 1)]];

Now you have X, with the values of x1,x2,x3.

X=[0.394876, 0.963263, 0.173956];

You can simply do this:

double(subs(A,x,X))

ans = 2×3

1.0000 0 0 -3.4478 -50.1285 95.5057

That stuffs the elements of X into x1,x2,x3 respectively. Then the call to double turns the result into numbers.