didier deshommes wrote: > On Thu, May 15, 2008 at 10:48 AM, Jason Grout > <[EMAIL PROTECTED]> wrote: >> More concisely, this proposal could be worded: >> >> What do people think of making matrix() return a matrix over a field by >> default, unless a ring is explicitly specified. The default field would >> either be the fraction field of the ring containing the specified >> elements, or would be QQ if no elements are specified. This logic would >> *only* be applied if a ring is not specified. The documentation of >> matrix() would also be changed accordingly. > > Just to make sure I get it: > matrix(1,1,[1]) and matrix(1,2,[Mod(23,4),23]) will be over QQ
Currently, your first example yields a matrix over ZZ and the second a matrix over Ring of integers mod 4. After the change, your first example would yield a matrix over QQ. The second would still yield a matrix over Ring of integers mod 4 because calling fraction_field throws an exception (the ring is not an integral domain). > > To me it looks like the *only* change from the current beahavior will > be that the matrices above will be over QQ, instead of over ZZ or a > generic ring. What other cases am I missing? A matrix over a polynomial ring, for example. sage: x=polygen(QQ) sage: matrix([x]).base_ring() Univariate Polynomial Ring in x over Rational Field After the change it would be: sage: x=polygen(QQ) sage: matrix([x]).base_ring() Fraction Field of Univariate Polynomial Ring in x over Rational Field Jason --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
