Question: Error, invalid boolean expression!!

> restart;
> with(LinearAlgebra);
> with(linalg);
> with(ArrayTools);
> n := 2;
> x := vector(n, []);
> x0 := vector(n, []);
> st := vector(n, []);
> for i to n do x0[i] := 0; st[i] := -1 end do;
> f := proc (x) options operator, arrow; x[1]^2-4*x[1]+x[2]^2-2*x[2] end proc;
         2                2         
x -> x[1]  - 4 x[1] + x[2]  - 2 x[2]
> lin := -4*x[1]-2*x[2];
                              -4 x[1] - 2 x[2]
> fin := grad(lin, [x[1], x[2]]);

> f0 := dotprod(x-x0, fin);
                              -4 x[1] - 2 x[2]
> xi := vector(n, []);
> with(Optimization); t := NLPSolve(f0, {x[1]                                      1.
                                     2.
> qwe := norm(x0-st, n);
> count := 1;
> if t < 0 then while qwe > 0, 1 do count := count+1; with(Optimization); k := NLPSolve(f(x0+alpha*(xi-x0)), {alpha >= 0, alpha = 0, alpha Error, invalid boolean expression
> print(t);
                                     -8.
>