why matlab tells me this?

f2=[o_1z*(l3x-p4x-s_x)*c1^4-2*c2*o_1z*(p4y+s_y)*c1^3+c3*(-l1^2+l4^2-l3x^2-l3y^2-l3z^2-p4x^2-p4y^2-p4z^2-s_x^2-s_y^2-s_z^2+2*l3y*o_1y+2*l3z*o_1z+2*o_1x*p4x-2*l3y*p4y+2*o_1y*p4y-2*l3z*p4z+2*o_1x*s_x-2*p4x*s_x+2*l3x*(-o_1x+p4x+s_x)-2*l3y*s_y+2*o_1y*s_y-2*p4y*s_y-2*l3z*s_z-2*p4z*s_z)...
    *c1^3+2*c2^2*l3x*o_1z*c1^2-2*o_1z(-l3x+p4x+s_x)*c1^2+4*c2*c3*(l3y*(-o_1x+p4x+s_x)+l3x*(-o_1y+p4y+s_y))*c1^2-2*c3*(o_1z*(p4y+s_y)+2*l3z*(-o_1y+p4y+s_y)+2*l3y*(o_1z-p4z-s_z))*c1^2+c2*(l1^2-l4^2+l3x^2+l3y^2+l3z^2+p4x^2+p4y^2+p4z^2+s_x^2+s_y^2+s_z^2-2*l3y*o_1y-2*l3z*o1z-2*o_1x*p4x+2*l3y*p4y-2*o_1y*p4y+2*l3z*p4z+2*l3x*(o_1x-p4x-s_x)-2*o_1x*s_x+2*p4x*s_x+2*l3y*s_y-2*o_1y*s_y+2*p4y*s_y+2*l3z*s_z+2*p4z*s_z)*c1^2-2*c3^2*(2*l3z*(o_1x-p4x-s_x)+l3x*(o_1z-2*(p4z+s_z)))*c1^2+4*c2^2*(l3y*(o_1x-p4x-s_x)+l3x*(o_1y-p4y-s_y))*c1-2*c2^3*o_1z*(p4y+s_y)*c1+c3^2*(4*l3y*(o_1x-p4x-s_x)+4*l3x*(-o_1y+p4y+s_y))*c1+c2*c3^2*(4*l3z*(-o_1y+p4y+s_y)-2*(o_1z*(p4y+s_y)+2*l3y*(o_1z-p4z-s_z)))*c1-8*c2*c3*l3x*(-o_1z+p4z+s_z)*c1+c2^2*c3*(-l1^2+l4^2-l3x^2-l3y^2-l3z^2-p4x^2-p4y^2-p4z^2-s_x^2-s_y^2-s_z^2-2*l3y*o_1y+2*l3z*o_1z+2*o_1x*p4x+2*l3y*p4y+...
    2*o_1y*p4y-2*l3z*p4z+2*o_1x*s_x-2*p4x*s_x-2*l3x*(-o_1x+p4x+s_x)+2*l3y*s_y+2*o_1y*s_y-2*p4y*s_y-2*l3z*s_z-2*p4z*s_z)*c1+c3^3*(-l1^2+l4^2-l3x^2-l3y^2-l3z^2-p4x^2-p4y^2-p4z^2-s_x^2-s_y^2-s_z^2+2*l3x*o_1x+2*l3y*o_1y-2*l3z*o_1z+2*o_1x*p4x-2*l3y*p4y+2*o_1y*p4y+2*l3z*p4z+2*o_1x*s_x-2*p4x*s_x-2*l3x*(p4x+s_x)-2*l3y*s_y+2*o_1y*s_y-2*p4y*s_y+2*l3z*s_z-2*p4z*s_z)*c1+c3*(-l1^2+l4^2-l3x^2-l3y^2-l3z^2-p4x^2-p4y^2-p4z^2-s_x^2-s_y^2-s_z^2-2*l3y*o_1y-2*l3z*o_1z+...
    2*o_1x*p4x+2*l3y*p4y+2*o_1y*p4y+2*l3z*p4z+2*o_1x*s_x-2*p4x*s_x+2*l3x*(-o_1x+p4x+s_x)+2*l3y*s_y+2*o_1y*s_y-2*p4y*s_y+2*l3z*s_z-2*p4z*s_z)*c1-2*c2*(2*l3z*(o_1y-p4y-s_y)+o_1z*(p4y+s_y)+2*l3y*(-o_1z+p4z+s_z))*c1+2*c3^2*l3x*o_1z+o_1z*(l3x-p4x-s_x)+c2^4*o_1z*(l3x+p4x+s_x)+c3^4*o_1z*(l3x+p4x+s_x)+2*c2^2*c3^2*o_1z*(l3x+p4x+s_x)+c2*c3*(4*l3y*(-o_1x+p4x+s_x)+4*l3x*(o_1y-p4y-s_y))-2*c3^3*o_1z*(p4y+s_y)-2*c3*o_1z*(p4y+s_y)...
    +c2*(l1^2-l4^2+l3x^2+l3y^2+l3z^2+p4x^2+p4y^2+p4z^2+s_x^2+s_y^2+s_z^2+2*l3y*o_1y+2*l3z*o_1z-2*o_1x*p4x-2*l3y*p4y-2*o_1y*p4y-2*l3z*p4z+2*l3x*(o_1x-p4x-s_x)-2*o_1x*s_x+2*p4x*s_x-2*l3y*s_y-2*o_1y*s_y+2*p4y*s_y-2*l3z*s_z+2*p4z*s_z)+c2*c3^2*(l1^2-l4^2+l3x^2+l3y^2+l3z^2+p4x^2+p4y^2+p4z^2+s_x^2+s_y^2+s_z^2-2*l3y*o_1y+2*l3z*o_1z-2*o_1x*p4x+2*l3y*p4y-2*o_1y*p4y-2*l3z*p4z-2*o_1x*s_x+2*p4x*s_x+2*l3x*(-o_1x+p4x+s_x)+2*l3y*s_y-2*o_1y*s_y+2*p4y*s_y-2*l3z*s_z...
    +2*p4z*s_z)+c2^3*(l1^2-l4^2+l3x^2+l3y^2+l3z^2+p4x^2+p4y^2+p4z^2+s_x^2+s_y^2+s_z^2+2*l3y*o_1y-2*l3z*o_1z-2*o_1x*p4x-2*l3y*p4y-2*o_1y*p4y+2*l3z*p4z-2*o_1x*s_x+2*p4x*s_x+2*l3x*(-o_1x+p4x+s_x)-2*l3y*s_y-2*o_1y*s_y+2*p4y*s_y+2*l3z*s_z+2*p4z*s_z)-2*c2^2*c3*(o_1z*(p4y+s_y)+2*l3z*(-o_1y+p4y+s_y)+2*l3y*(-o_1z+p4z+s_z))+c2^2*(4*l3z*(o_1x-p4x-s_x)-2*l3x*(o1z-2*(p4z+s_z)))];

Error using ^

Matrix must be square.

why?

Answer 1

[Rik]

Lets take a third power as example.

A is n by m
A^3 = A*A*A = [n x m]*[n x m]*[n x m]
To be compatible, adjacent sizes must be equal
Therefore, for this operation to be valid, n and m must be equal

If instead you meant element-wise operations, you should replace all matrix operation with the other version. That means replacing every * with .* and every ^ with .^ (plus and minus will always work element-wise).

I hope this formula was generated procedurally and not written by hand, because that would be a nightmare to debug. Especially with all those numbered variables, instead of arrays.

[sebastiano della gatta]

thank you.