Hi! On Sep 4, 10:10 am, Simon King <[email protected]> wrote: > I don't know whether it would suffice to define an integer matrix "a" > in the Singular interface, though. Let me do some tests.
Apparently it isn't that easy. And also I believe that defining an integer matrix in the Singular interface and then referring to it from a Sage session in order to define a matrix ordering is no good style. So, before changing too much, let us do some "brain storming": How should a clean solution look like? Apparently it would be nice to define a matrix ordering by a matrix, such as sage: M=Matrix(2,2,[1,3,1,0]) sage: R.<x,y> = PolynomialRing(QQ,2,order=M) Hence, order should not necessarily be a string. One problem with a string is: If you try to do order='M(1,3,1,0)' then not only will 'M' be transformed into 'm', but also it is assumed that you want to define a block ordering, since the string contains a comma. So, sticking to strings would imply: The pattern matching must be improved. But if "order" can be a matrix, then how would one define a block ordering? I guess this would be done by a list or tuple, whose entries are either matrices or strings, such as: sage: P.<a,b,c,d,e> = PolynomialRing(QQ,5,order=[M,'degrevlex']) However, for backwards compatibility, it should still be possible to define blocks by strings. What do people think? * Should it (in addition to the current behaviour) be possible to define a matrix ordering by a matrix and a block ordering by a list or tuple? * Should "order" always be a string, but allowing for order='M (1,3,1,0),degrevlex(3)', for example? * Or, since the Sage syntax for term orderings is different from Singular syntax anyway, perhaps it should be order='[[1,3], [1,0]],degrevlex(3)'? I am more in favour of the second or third solution. Best regards, Simon --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
