How to retrieve the 'infeasibilities.txt' from the gekko

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I've got an infeasibility error message from GEKKO simulation. I want to retrieve the 'infeasibilities.txt' file for debugging the algorithm.

Please let me know where I can find the file. 

R1 = m.Intermediate(3/r0/W*((A3*(A2+B2+B3+F)+(A2+B2)*(B3+F))*(cg0[0]-ceq1) \
                     -(A3*(B2+B3+F)+B2*(B3+F))*(cg0[0]-ceq2) \
                     -A2*(B3+F)*(cg0[0]-ceq3)))
R2 = m.Intermediate(3/r0/W*(-(B2*(A3+B3+F)+A3*(B3+F))*(cg0[0]-ceq1) \
                     +((A1+B1+B2)*(A3+B3+F)+A3*(B3+F))*(cg0[0]-ceq2) \
                     -(A1+B1)*(B3+F)*(cg0[0]-ceq3)))
R3 = m.Intermediate(3/r0/W*(-A2*(B3+F)*(cg0[0]-ceq1) \
                    -(A1+B1)*(B3+F)*(cg0[0]-ceq2) \
                    +((A1+B1)*(A2+B2+B3+F)+A2*(B2+B1+F))*(cg0[0]-ceq3)))

m.Equation(cH.dt() == nus[0].dot([R1, R2, R3]))
m.Equation(cM.dt() == nus[1].dot([R1, R2, R3]))
m.Equation(cW.dt() == nus[2].dot([R1, R2, R3]))
m.Equation(cF.dt() == nus[3].dot([R1, R2, R3]))

m.options.IMODE = 4
m.options.SOLVER = 3
m.options.nodes = 2

Creating file: infeasibilities.txt

Use command apm_get(server,app,'infeasibilities.txt') to retrieve file

error: Solution Not Found

gekko python debugging
1 Answers

There are two ways to access the file. The first method is to switch to remote=False to solve locally and produce the infeasibilities.txt file on your computer. The second method is to retrieve the file from the remote directory. The first method is the most simple solution in terms of coding (just change an option and open the run folder). The second method is most convenient because it makes the file available in your run directory. The example that I include below is purposefully infeasible with equations x+y=1 and x+y=0.

Method 1 - Open run folder when remote=False

from gekko import GEKKO
m = GEKKO(remote=False) # remote=False to produce local folder with results          
x = m.Var()    
y = m.Var()
m.Equations([x+y==1, x+y==0])  # no solution
m.open_folder() # open folder if remote=False to see infeasibilities.txt
m.solve(disp=True)    # solve

Method 2 - Retrieve infeasibilities.txt file when remote=True

from gekko import GEKKO
m = GEKKO(remote=True)          
x = m.Var()    
y = m.Var()
m.Equations([x+y==1, x+y==0])  # no solution
try:
    m.solve(disp=True)    # solve
except:
    print('Not successful')
    from gekko.apm import get_file
    print(m._server)
    print(m._model_name)
    f = get_file(m._server,m._model_name,'infeasibilities.txt')
    f = f.decode().replace('\r','')
    with open('infeasibilities.txt', 'w') as fl:
        fl.write(str(f))

The infeasibilities.txt file is somewhat hard to read but it does try to identify equations that are causing the solution to fail. Here is the example from this problem.

************************************************
***** POSSIBLE INFEASBILE EQUATIONS ************
************************************************
____________________________________________________________________________
EQ Number   Lower        Residual     Upper        Infeas.     Name
         1   0.0000E+00  -9.4140E-01   0.0000E+00   9.4140E-01  ss.Eqn(1): 0 = (v1+v2)-(1)
 Variable   Lower        Value        Upper        $Value      Name
         1  -1.2346E+20   2.9300E-02   1.2346E+20   0.0000E+00  ss.v1
         2  -1.2346E+20   2.9300E-02   1.2346E+20   0.0000E+00  ss.v2
____________________________________________________________________________
EQ Number   Lower        Residual     Upper        Infeas.     Name
         2   0.0000E+00   5.8600E-02   0.0000E+00  -5.8600E-02  ss.Eqn(2): 0 = (v1+v2)-(0)
 Variable   Lower        Value        Upper        $Value      Name
         1  -1.2346E+20   2.9300E-02   1.2346E+20   0.0000E+00  ss.v1
         2  -1.2346E+20   2.9300E-02   1.2346E+20   0.0000E+00  ss.v2
************************************************
****** ACTIVE OBJECTIVE EQUATIONS **************
************************************************
Number           ID  Node    Horizon  Unscaled Res  Scaled Res   Scaling     Name
************************************************
************* ACTIVE EQUATIONS *****************
************************************************
Number           ID  Node    Horizon  Unscaled Res  Scaled Res   Scaling     Name
         1          1    1          1  -9.4140E-01  -9.4140E-01   1.0000E+00  ss.Eqn(1): 0 = (v1+v2)-(1)
         2          2    1          1   5.8600E-02   5.8600E-02   1.0000E+00  ss.Eqn(2): 0 = (v1+v2)-(0)
************************************************
************ INACTIVE EQUATIONS ****************
************************************************
Number     Unscaled Res    Scaled Res   Scaling      Name

If you use x = m.Var(name='x') to name your variables then the file will become more descriptive. Both equations were identified as potentially infeasible.

user_23669410
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