bug in LinearProgramming?
- To: mathgroup at smc.vnet.net
- Subject: [mg95238] bug in LinearProgramming?
- From: Veit Elser <ve10 at cornell.edu>
- Date: Sun, 11 Jan 2009 06:40:42 -0500 (EST)
Here is a simple linear programming problem:
c = {1, 1};
m = {{1, 0}, {1, -2}, {-1, 1}};
b = {{1, 0}, {0, 1}, {0, 1}};
lu = {{0, 1}, {0, 1}};
d = {Reals, Reals};
sol = LinearProgramming[c, m, b, lu, d]
Mathematica 6 returns:
LinearProgramming::"lpsnf" : "No solution can be found that
satisfies the constraints."
which is obviously correct. But if I change the domain of the second
variable,
d = {Reals, Integers};
then Mathematica gives the solution
sol = {1., 1}. The problem is that
m.sol = {1., -1., 0.}
violates the bound vector b (second component should be greater than 0).
Is there a bug, or am I getting the syntax wrong?
Veit Elser