On Mon, May 3, 2010 at 12:50 PM, Diego Ruano <dru...@gmail.com> wrote:
> Thank you David for your answer.
>
> What about getting a solution over the integers?
I'm sure of the best way. You could just write your own
little function that checks the conditions for each
(i,j) in a big rectangle. Also, you might be able to use Sage's
MixedIntegerLinearProgram functionality.
Hopefully others on this list will have a better idea.
>
> David Joyner wrote:
>> I think Sage calls Maxima and Maxima is getting i (your variable)
>> and I (sqrt(-1)) mixed up. I guess this is a bug, but it might be
>> known already.
>>
>> Anyway, using x's and y's might be safer:
>>
>> sage: x,y = var('x,y')
>> sage: ineqs = [2*x+9*y>= - 0, -5*x-7*y>=-5, 3*x-2*y>= -6]
>> sage: solve_ineq(ineqs,[x,y])
>> [[x == (-32/31), y == (45/31)], [x == (-54/31), y == (12/31)], [x ==
>> 2/3*y - 2, (12/31) < y, y < (45/31)], [x == (45/31), y == (-10/31)],
>> [x == -7/5*y + 1, (-10/31) < y, y < (45/31)], [x == -9/2*y, (-10/31) <
>> y, y < (12/31)], [max(2/3*y - 2, -9/2*y) < x, x < -7/5*y + 1, (-10/31)
>> < y, y < (45/31)]]
>>
>>
>>
>>
>>
>> On Mon, May 3, 2010 at 5:04 AM, Diego Ruano <dru...@gmail.com> wrote:
>> > Hi,
>> >
>> > I would like to compute the solution of systems of inequalities over
>> > the integers. I have used the command "solve", but the solution is
>> > over the complex numbers.
>> >
>> > Something like:
>> >
>> > i, j = var('i,j')
>> > sol=solve([2*i+9*j>= - 0, -5*i-7*j>=-5, 3*i-2*j>= -6], i,j)
>> > sol
>> > [[i == (-54/31), j == (12/31)], [i == (-32/31), j == (45/31)], [i ==
>> > (45/31), j == (-10/31)], [i == -7/5*j + 1, (-10/31) < j, j <
>> > (45/31)], [i == -9/2*j, (-10/31) < j, j < (12/31)], [i == 2/3*j -
>> > 2, (12/31) < j, j < (45/31)], [max(2/3*j - 2, -9/2*j) < i, i
>> > < -7/5*j + 1, (-10/31) < j, j < (45/31)]]
>> >
>> > Is there any way to get the intersection of the previous set with
>> > ZZ^2?, or a command to solve the system over the integers?
>> >
>> > Thanks,
>> >
>> > Diego
>> >
>> > --
>> > To post to this group, send email to sage-support@googlegroups.com
>> > To unsubscribe from this group, send email to
>> > sage-support+unsubscr...@googlegroups.com
>> > For more options, visit this group at
>> > http://groups.google.com/group/sage-support
>> > URL: http://www.sagemath.org
>> >
>>
>> --
>> To post to this group, send email to sage-support@googlegroups.com
>> To unsubscribe from this group, send email to
>> sage-support+unsubscr...@googlegroups.com
>> For more options, visit this group at
>> http://groups.google.com/group/sage-support
>> URL: http://www.sagemath.org
>
> --
> To post to this group, send email to sage-support@googlegroups.com
> To unsubscribe from this group, send email to
> sage-support+unsubscr...@googlegroups.com
> For more options, visit this group at
> http://groups.google.com/group/sage-support
> URL: http://www.sagemath.org
>
--
To post to this group, send email to sage-support@googlegroups.com
To unsubscribe from this group, send email to
sage-support+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/sage-support
URL: http://www.sagemath.org
