from gekko import GEKKO
m = GEKKO(remote=False) # create GEKKO model
y = m.Var(5.0,name='y') # create GEKKO variable
m.Equation(y.dt()==-y)  # create GEKKO equation
m.time = [0,1,2,3]      # time points
m.options.IMODE = 4     # simulation mode
m.options.NODES = 4     # set NODES=4
m.options.CSV_WRITE=2   # write results_all.json
                        #   with internal nodes
m.solve()               # solve
m.open_folder()         # open run folder to see
                        #   source and results files

import matplotlib.pyplot as plt
# plot at [0,1,2,3]
plt.plot(m.time,y,'ro')

# retrieve internal nodes from results_all.json
import json
with open(m.path+'//results_all.json') as f:
    results = json.load(f)
plt.plot(results['time'],results['y'],'bx')    
plt.show()