Computing polyhedron from MIP
I want to run the following code (I'm using SAGE v6.10 release version 2015-12-18):
P = MixedIntegerLinearProgram()
x = P.new_variable()
A = random_matrix(RR, 3, 2);
P.add_constraint(A*x <= [2.1,1.5,0.4])
P.polyhedron()
However, it outputs the error message:
AttributeError: type object 'float' has no attribute 'fraction_field'
I noticed that if instead of using real variables I use only integer variables, then it works fine. For instance:
P = MixedIntegerLinearProgram()
x = P.new_variable()
A = random_matrix(ZZ, 3, 2);
P.add_constraint(A*x <= [2,1,0])
P.polyhedron()
outputs:
A 2-dimensional polyhedron in QQ^2 defined as the convex hull of 1 vertex and 2 rays
What do you suggest to overcome this problem?
Thanks
About 2 years ago (not sure which version of Sage that was), the polyhedron worked. But, it appears to be an issue now.
Thanks. Anyway, I should try installing sagemath v7.2.
Adding
confirmed_bug
tag, and a link to trac ticket 23326.@tmonteil : great, thanks.
It is fixed in 8.0