Ciao everyone ! I'm trying to make some computation with matrices (with some variables x,y,z). For that, I'm following the document : http://www.sagenb.org/home/pub/217/
When I type (in a notebook) the following, it works : ++++++++++++++++++++ A = matrix([[7, 0, 0], [0, -2, 4], [0, 6, 0]]) I3 = identity_matrix(QQ, 3) L = var('L') CE1 = det(L*I3 - A) print(CE1) ++++++++++++++++++ It produces the characteristic polynomial of the matrix A. But the slightest change produce a wide variety of crashes or unexpected thinks. For example, if I define an itermediate matrix B build from A : +++++++++++++++++++++++++++++ A = matrix([[7, 0, 0], [0, -2, 4], [0, 6, 0]]) I3 = identity_matrix(QQ, 3) L = var('L') B = L*I3 - A print(B) CE1 = det(L*I3 - A) print(CE1) ++++++++++++++++++++++++++ produces : ------------------------------------------------------------------------- Maxima crashed -- automatically restarting. execfile("/home/kusbiste/.sage/sage_notebook/worksheets/admin/3/code/5.p\ y") print "\x01r\x01e4" >>> print "\x01r\x01e3" r e3 >>> execfile("/home/kusbiste/.sage/sage_notebook/worksheets/admin/3/code/5.p\ y") b4 Maxima crashed -- automatically restarting. execfile("/home/kusbiste/.sage/sage_notebook/worksheets/admin/3/code/5.p\ y") print "\x01r\x01e4" >>> print "\x01r\x01e3" r e3 >>> execfile("/home/kusbiste/.sage/sage_notebook/worksheets/admin/3/code/5.p\ y") b4 Maxima crashed -- automatically restarting. execfile("/home/kusbiste/.sage/sage_notebook/worksheets/admin/3/code/5.p\ y") print "\x01r\x01e4" >>> print "\x01r\x01e3" r e3 >>> execfile("/home/kusbiste/.sage/sage_notebook/worksheets/admin/3/code/5.p\ y") b4 Maxima crashed -- automatically restarting. Traceback (click to the left for traceback) ... TypeError: unable to make sense of Maxima expression 'sage26[3,3]' in SAGE ------------------------------------------------------------------------- If I copy/paste exactly these lines in the terminal interface of sage, I get the expected result : +++++++++++++++++++++++++++++++++++ $ sage ---------------------------------------------------------------------- | SAGE Version 3.0.5, Release Date: 2008-07-11 | | Type notebook() for the GUI, and license() for information. | ---------------------------------------------------------------------- sage: A = matrix([[7, 0, 0], [0, -2, 4], [0, 6, 0]]) sage: I3 = identity_matrix(QQ, 3) sage: L = var('L') sage: B = L*I3 - A sage: print(B) [L - 7 0 0] [ 0 L + 2 -4] [ 0 -6 L] sage: CE1 = det(L*I3 - A) sage: print(CE1) (L - 7) (L (L + 2) - 24) sage: ++++++++++++++++++++++++++++++++++++++++++++ Any ideas ? My aim is to do the following : I would like to define 4 matrices q0,q1,q2,q3 and then a function which creates a linear combination of them: +++++++++++++++++++++++++ def Q(w1,w2,w3): s = q0+w1*q1+w2*q2+w3*q3 return s x = var('x') print Q(x,1,3) +++++++++++++++++++++++++++ That construction produces very different results when I try slight differences. Any help is much welcome. Thanks Have a good day Laurent --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---