Subscript indices must either be real positive integers or logicals .. ERROR

This is a part of my code, when I run it .. I got this message

• *{ Subscript indices must either be real positive integers or logicals.

Error in proj (line 131)

inv=inv(D+aL);

}* *

what is the problem?

D=diag(diag®); %Diagnoal

L=tril(R,-1); %Lower-Triangular matrix

U=triu(R,1); %Upper-Triangular matrix

aL=a*L; %Relaxation Factor with lower-traingular matrix

inv=inv(D+aL);

prak=(((1-a)*D)-(a*U));

B=inv*prak;

c=(a*inv)*V;

cur=I;

condition3=1;

k2=0;

[Sara]

what is a?

Answer 1

[Azzi Abdelmalek]

Your function inv is erased by the variable inv

inv=inv(D+aL)

change it to

inv1=inv(D+al)

[Fatima Al Marzoqi]

it works , thank you