function x = LTriSol(L,b)
n=length(b);
x=zeros(n,1);
for i=1:n
    xsum=0.0;
    for j=1:i-1
        xsum=xsum-x(j)*L(i,j);
    end
x(i)=(b(i)+ xsum)/L(i,i);   
end
end