from gekko import GEKKO
m = GEKKO()
x1 = m.Var(-3)
x2 = m.Var(2)
m.Minimize(x1**2-2*x1*x2+4*x2**2)
m.options.SOLVER = 2 # 1=APOPT, 2=BPOPT, 3=IPOPT
m.solve()
print(x1.value[0],x2.value[0])