cell array error using equationsToMatrix function

Question

Emiliano Rosso 2023-4-6

回答： Emiliano Rosso 2023-4-6

Hi

in reference to :

I must use this code :

syms x y z
eqn1 = 2*x + y + z == 2;
eqn2 = -x + y - z == 3;
eqn3 = x + 2*y + 3*z == -10;
[A,B] = equationsToMatrix([eqn1, eqn2, eqn3], [x, y, z])

but using cell array.

So I do:

a=cell(1,3);
b=cell(1,3);
a{1}=eqn1;a{2}=eqn2;a{2}=eqn3;
b{1}=x;b{2}=y;b{3}=z;

Using one cell at a time I obtain the same results :

[A,B] = equationsToMatrix([a, [x, y, z]);
[A,B] = equationsToMatrix([eqn1, eqn2, eqn3], b)

but when I use both :

[A,B] = equationsToMatrix(a, b)
Check for missing argument or incorrect argument data type in call to function 'equationsToMatrix'.

How to solve this error?

Thanks!

Answer 1

Emiliano Rosso 2023-4-6

Instead of using cell use syms:

a=syms(1,3);
b=syms(1,3)
a(1)=eqn1;a(2)=eqn2;a(3)=eqn3;
b(1)=x;b(2)=y;b(3)=z;
[A,B] = equationsToMatrix(a, b);