from gekko import GEKKO
m = GEKKO() # create GEKKO model
#integer variable
x1 = m.Var(integer=True,lb=-5,ub=10) 
#create Special Ordered Set variable
x2 = m.sos1([0.5, 1.15, 2.6, 5.2])
#continuous variable
x3 = m.Var(lb=0)
m.Minimize(4*x1**2-4*x2*x1**2+x2**2+x1**2-x1+x3**2)
m.Equation(x3*x2>=1)
m.options.SOLVER = 1 # APOPT solver
m.solve(disp=False)
print('x1: ' + str(x1.value[0]))
print('x2: ' + str(x2.value[0]))
print('x3: ' + str(x3.value[0]))