[petsc-users] Variatonal inequalities

[Barry Smith]

  David,

   Currently the only way to do this without adding a lot of additional PETSc code is to add additional variables such that only box constraints appear in the final problem. For example say you have constraints   c <= Ax <= d then introduce new variables y = Ax and then you have the larger problem of unknowns (x,y) and box constrains on y with -infinity and +infinity constraints on x. 

  Barry

> On Aug 22, 2015, at 6:59 AM, David Knezevic <david.knezevic at akselos.com> wrote:
> 
> Hi all,
> 
> I see from Section 5.7 of the manual that SNES supports box constraints on variables, which is great. However, I was also hoping to also be able to consider general linear inequality constraints, so I was wondering if anyone has any suggestions on how (or if) that could be done with PETSc?
> 
> Thanks,
> David
>