Write datalog programs

[wangk7]

Hi,

I'm a new Myria user and trying to write some datalog programs by using Myria Demo Service. I want to get the logical plan for a datalog program. It worked for simple datalog queries, for example, "A(x,z) :- R(x,y), R(y,z)". But when I was trying "CC(x,$Min(z)) :- CC(x,z), Edges(x,z) " or "TC(x,z) :- TC(x,y), Edges(y,z)", there were some exceptions. It seems the same predicate can not be in both head and body? I'm wondering how should I write datalog programs under myria?

Thank you.