How do I find GEKKO application success status?
Question:
I am running m.solve() in a try .. except construct to elegantly handle any exceptions raised by the solver due to maximum iterations or convergence to an infeasibility but want to interrogate APPINFO and APPSTATUS to determine if a solution was found. I was surprised to see that I always seem to get APPINFO=0 and APPSTATUS=1 even though the the solver reports that a solutions was not found.
What am I missing in my interpretation of the document on APPINFO and APPSTATUS?
Piece of code to reproduce error.
from gekko import GEKKO
m=GEKKO(remote=False)
m.x=m.Var()
m.y=m.Var()
m.total=m.Intermediate(m.x+m.y)
m.Equation(m.total>20) #if included, no feasible solution exists
m.Equation(m.x<9)
m.Equation(m.y<9)
m.Maximize(m.total)
m.options.SOLVER=3
try:
m.solve()
except Exception as e:
print('Exception',e)
print('APPINFO', m.options.APPINFO)
print('APPSTATUS', m.options.APPSTATUS)
Answers:
Use debug=False to not raise an exception when Gekko fails to solve. When there is an exception, the results are not loaded back into m.options.
from gekko import GEKKO
m=GEKKO(remote=False)
m.x=m.Var()
m.y=m.Var()
m.total=m.Intermediate(m.x+m.y)
m.Equation(m.total>20) #if included, no feasible solution exists
m.Equation(m.x<9)
m.Equation(m.y<9)
m.Maximize(m.total)
m.options.SOLVER=3
m.solve(debug=False)
print('APPINFO', m.options.APPINFO)
print('APPSTATUS', m.options.APPSTATUS)
This produces the correct error response:
---------------------------------------------------
Solver : IPOPT (v3.12)
Solution time : 0.0156 sec
Objective : -18.023281704731964
Unsuccessful with error code 0
---------------------------------------------------
Creating file: infeasibilities.txt
Use command apm_get(server,app,'infeasibilities.txt') to retrieve file
@error: Solution Not Found
APPINFO 2
APPSTATUS 0
I am running m.solve() in a try .. except construct to elegantly handle any exceptions raised by the solver due to maximum iterations or convergence to an infeasibility but want to interrogate APPINFO and APPSTATUS to determine if a solution was found. I was surprised to see that I always seem to get APPINFO=0 and APPSTATUS=1 even though the the solver reports that a solutions was not found.
What am I missing in my interpretation of the document on APPINFO and APPSTATUS?
Piece of code to reproduce error.
from gekko import GEKKO
m=GEKKO(remote=False)
m.x=m.Var()
m.y=m.Var()
m.total=m.Intermediate(m.x+m.y)
m.Equation(m.total>20) #if included, no feasible solution exists
m.Equation(m.x<9)
m.Equation(m.y<9)
m.Maximize(m.total)
m.options.SOLVER=3
try:
m.solve()
except Exception as e:
print('Exception',e)
print('APPINFO', m.options.APPINFO)
print('APPSTATUS', m.options.APPSTATUS)
Use debug=False to not raise an exception when Gekko fails to solve. When there is an exception, the results are not loaded back into m.options.
from gekko import GEKKO
m=GEKKO(remote=False)
m.x=m.Var()
m.y=m.Var()
m.total=m.Intermediate(m.x+m.y)
m.Equation(m.total>20) #if included, no feasible solution exists
m.Equation(m.x<9)
m.Equation(m.y<9)
m.Maximize(m.total)
m.options.SOLVER=3
m.solve(debug=False)
print('APPINFO', m.options.APPINFO)
print('APPSTATUS', m.options.APPSTATUS)
This produces the correct error response:
---------------------------------------------------
Solver : IPOPT (v3.12)
Solution time : 0.0156 sec
Objective : -18.023281704731964
Unsuccessful with error code 0
---------------------------------------------------
Creating file: infeasibilities.txt
Use command apm_get(server,app,'infeasibilities.txt') to retrieve file
@error: Solution Not Found
APPINFO 2
APPSTATUS 0