On Jun 20, 10:18 pm, Robert Bradshaw <rober...@math.washington.edu> wrote: > sage: n = 10 > sage: m = block_matrix([0, zero_matrix(1,1), identity_matrix(n), 0]) > sage: m.subdivide() # get rid of the block divisions > sage: m > [0 0 0 0 0 0 0 0 0 0 0] > [1 0 0 0 0 0 0 0 0 0 0] > [0 1 0 0 0 0 0 0 0 0 0] > [0 0 1 0 0 0 0 0 0 0 0] > [0 0 0 1 0 0 0 0 0 0 0] > [0 0 0 0 1 0 0 0 0 0 0] > [0 0 0 0 0 1 0 0 0 0 0] > [0 0 0 0 0 0 1 0 0 0 0] > [0 0 0 0 0 0 0 1 0 0 0] > [0 0 0 0 0 0 0 0 1 0 0] > [0 0 0 0 0 0 0 0 0 1 0] > > You can also use this to get anything you want on the sub-diagonal > (or pretty much anywhere). > > sage: m = block_matrix([0, zero_matrix(1,1), diagonal_matrix([10, 20, > 30, 40]), 0]); m.subdivide(); m > [ 0 0 0 0 0] > [10 0 0 0 0] > [ 0 20 0 0 0] > [ 0 0 30 0 0] > [ 0 0 0 40 0]
Very nice - I didn't know about block_matrix. In addition, it seems block_matrix has an optional argument "subdivide". sage: n = 10 sage: m = block_matrix([0, zero_matrix(1,1), identity_matrix(n), 0],subdivide=False) sage: m [0 0 0 0 0 0 0 0 0 0 0] [1 0 0 0 0 0 0 0 0 0 0] [0 1 0 0 0 0 0 0 0 0 0] [0 0 1 0 0 0 0 0 0 0 0] [0 0 0 1 0 0 0 0 0 0 0] [0 0 0 0 1 0 0 0 0 0 0] [0 0 0 0 0 1 0 0 0 0 0] [0 0 0 0 0 0 1 0 0 0 0] [0 0 0 0 0 0 0 1 0 0 0] [0 0 0 0 0 0 0 0 1 0 0] [0 0 0 0 0 0 0 0 0 1 0] --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
