How to add a value to a already existing matrix?

KB=[1 3;4 5] for i:Nbarras Mgl(i,1)= Mgl(i,1) + KB(i,1)

which method is correct? for i:Nbarras Mgl(i,1)= Mgl(i,1) + KB(i,1)

or for i:Nbarras Mgl(i,1)=+KB(i,1)

or somehow else?

Answer 1

[Mahesh]

I hope the correct one, if you have already defined Mgl, is

   Mgl(1,1)= Mgl(1,1) + KB(1,1)

Good luck

[Rachuan]

When i do it like that it shows

"Undefined function 'Mgl' for input arguments of type 'double'."

[Mahesh]

you need to define Mgl matrix if you do not have like

Mgl = zeros(2,2)