Metode numerice - Alex Suciu

function X = elim(fisier)
    v = load(fisier);
    a = size(v);
    a = a(1,2);
    n = 2+(a-6)/4;
    c = 3;
    a(1) = 0;
    b(1) = v(1);
    c1(1) = v(2);
    for i = 2:n-1
       a(i)=v(c);
        b(i)=v(c+1);
        c1(i)=v(c+2);
        c=c+3;
    end
    c1(n) = 0;
    a(n) = v(c);
    b(n) = v(c+1);
    c=c+1;
    for i = 1:n
        t_liber(i) = v(c+i);
    end
    if(n > 100)
        X = tridi(a, b, c1, t_liber);
    else
        %Aici bagi o eliminare gaussiana
        X = zeros(1, n);
    endif
    dlmwrite("date.out", X);
end

function d = tridi(a, b, c, d)
    %Intrari    a = subdiagonala
    %       b = diagonala principala
    %       c = supradiagonala
    %       d = vectorul termenilor liberi
    a = a(:);
    n = length(b);
    for i=2:n
        t = a(i) / b(i-1);
        b(i) = b(i) - t*c(i-1);
        d(i) = d(i) - t*d(i-1);
    endfor
    d(n) = d(n) / b(n);
    for i = n-1: -1:1
        d(i) = (d(i) - c(i)*d(i+1)) / b(i);
    endfor
endfunction