Different results when I print the program

[marcsans]

I have different results when I print my model before solving it. On simple cases, I get the wrong answer without printing the model before and I get the write answer when I print the model.

I use a object oriented structure : my pycpx model is a property of a class and so are the variables and constraints. I use linked lists and matrix to store the variables.

I also noticed something before discovering this "print model" trick: I solved the program and make pycpx give me the left and right term of a constraint, I found a constraint that was not satisfied. However, the right term was given between [[ and ]] whereas the right term was given as a float number.

This is my function :

def solveMblp(self):
    print self.m
    bsum = self.b[0].sum()
    for k in range(1, len(self.b)):
        bsum += self.b[k].sum()
    self.m.maximize(bsum)

Please ask me for the full code if you need it.