Are non-pointed fans supported?

[Drew]

Some parts of the documentation for application fan say that fans with non-trivial lineality are not supported, and some say that they are. What is true?

[assarf]

They are supported. You can define non-pointed fans... meaning that each cone of the fan has the same LINEALITY_SPACE. But there are some algorithms which have the precondition that the input should be a pointed fan. Often those algorithms can be generalized for the non pointed situation, but it just is not implemented yet. In those situations you can try and use the "pointed algorithm" as a black box and handle the LINEALITY_SPACE on your own.

[Drew]

Thank you! So I will ignore the part in the documentation that says:

LINEALITY_DIM: common::Int

Dimension of LINEALITY_SPACE. FIXME currently polymake can only handle POINTED cones


I hope that polymake will give me an error or warning if I use a algorithm that is not compatible with non-pointed cones.

[assarf]

Thank you! So I will ignore the part in the documentation that says:

LINEALITY_DIM: common::Int

Dimension of LINEALITY_SPACE. FIXME currently polymake can only handle POINTED cones

Can you post the link to that part of the documentation?

I hope that polymake will give me an error or warning if I use a algorithm that is not compatible with non-pointed cones.

Yes. Whenever an algorithm needs some precondition it will give you an error when that precondition is not satisfied.