ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Tue, 14 Jun 2016 14:09:09 +0200Computing polyhedron from MIPhttps://ask.sagemath.org/question/33782/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?
ThanksmforetsTue, 14 Jun 2016 14:09:09 +0200https://ask.sagemath.org/question/33782/How to cast a string with an exponent from sys.argv to an Integer ?https://ask.sagemath.org/question/29597/how-to-cast-a-string-with-an-exponent-from-sysargv-to-an-integer/Hi,
For an exercise, I have written a Python script that takes an integer argument. Of course, the input in sys.argv is of type 'str', so I cast it to an Integer. It works, but I am supposed to accept numbers written like '123^1237' too, with a hat for the exponent. And I cannot find how to do that. In the sage interpreter, I can type "n = Integer(123^1237)" without any problem, but in my script it fails with a "TypeError: unable to convert '123^1237' to an integer". ThanksOnoxSat, 26 Sep 2015 17:00:01 +0200https://ask.sagemath.org/question/29597/