%sistema tri diagonal function[x]=solve_tri(a,b) n=length(b); for k = 1:n %pivotagem parcial [modpivot,q]=max(abs(a(k:k+1,k))); q=q+k-1; if(q~=k); auxq=a(q,k:n); a(q,k:n)=(k,k:n); a(k,k:n)=auxq; auxb=b(q); b(k)=auxb; end %triangularizaçao i=k+1; mult=a(i,k)/a(k,k); a(i,k)=0.0; a(i,k+1:n)=a(i,k+1:n); b(i)=b(i)-mult*b(k); end x=zeros(n,1); x(n)=b(n)/a(n,n); for i=n-1:-1:1 soma=(i,i+1:n)*x(i+1:n); x(i)=b(i)-soma/a(i,i); end; return;