Hi A lecturer returned a year after we posted some messagses, resulting in some bugs identified, some fixed and some still open.
The Quantum Spin Chain course repeated now on sage 4.2.1, still computing eigenmatrix'es and involving complex numbers. We try to isolate the problems clearly here: History http://groups.google.com/group/sage-support/browse_thread/thread/2aa691129fdca1d3 http://trac.sagemath.org/sage_trac/ticket/4725 http://trac.sagemath.org/sage_trac/ticket/4726 http://trac.sagemath.org/sage_trac/ticket/4727 http://groups.google.com/group/sage-support/browse_thread/thread/9f2ee99b8da95c6 http://trac.sagemath.org/sage_trac/ticket/4834 Current status 0 j...@capetown:~$sage ---------------------------------------------------------------------- | Sage Version 4.2, Release Date: 2009-10-24 | | Type notebook() for the GUI, and license() for information. | ---------------------------------------------------------------------- Loading Sage library. Current Mercurial branch is: AIMS-autosave-patch sage: py=matrix([[0,-I],[I,0]]) # matrix contains I sage: py.eigenmatrix_right() # does not work because of I /home/jan/.sage/temp/capetown/27537/_home_jan__sage_init_sage_0.py:1: UserWarning: Using generic algorithm for an inexact ring, which may result in garbage from numerical precision issues. # -*- coding: utf-8 -*- /home/jan/.sage/temp/capetown/27537/_home_jan__sage_init_sage_0.py:1: UserWarning: Using generic algorithm for an inexact ring, which will probably give incorrect results due to numerical precision issues. # -*- coding: utf-8 -*- --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /home/jan/.sage/temp/capetown/27537/_home_jan__sage_init_sage_0.py in <module>() /usr/local/src/sage-4.2/local/lib/python2.6/site-packages/sage/matrix/matrix2.so in sage.matrix.matrix2.Matrix.eigenmatrix_right (sage/matrix/matrix2.c:23778)() /usr/local/src/sage-4.2/local/lib/python2.6/site-packages/sage/matrix/matrix2.so in sage.matrix.matrix2.Matrix.eigenmatrix_left (sage/matrix/matrix2.c:23463)() /usr/local/src/sage-4.2/local/lib/python2.6/site-packages/sage/matrix/matrix2.so in sage.matrix.matrix2.Matrix.eigenvectors_left (sage/matrix/matrix2.c:22794)() /usr/local/src/sage-4.2/local/lib/python2.6/site-packages/sage/matrix/matrix2.so in sage.matrix.matrix2.Matrix.eigenspaces_left (sage/matrix/matrix2.c:21406)() TypeError: degree() takes exactly one argument (0 given) sage: sage: K.<j>=QQ[sqrt(-1)] sage: j I sage: newpy=matrix([[0,-j],[j,0]]) sage: newpy.eigenmatrix_right() # now it works ([ 1 0] [ 0 -1], [ 1 1] [ I -I]) sage: pysquare=py*py; pysquare [1 0] [0 1] sage: newpysquare= newpy*newpy; newpysquare [1 0] [0 1] sage: v1=vector([1,1]);v1 (1, 1) sage: v2=vector([1,-1]);v2 (1, -1) sage: var('a') a sage: pysquare*(v1+a*v2) # This works OK (a + 1, -a + 1) sage: newpysquare*(v1+a*v2) # But the same thing with the square of newpy does NOT work --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /home/jan/.sage/temp/capetown/27537/_home_jan__sage_init_sage_0.py in <module>() /usr/local/src/sage-4.2/local/lib/python2.6/site-packages/sage/structure/element.so in sage.structure.element.Matrix.__mul__ (sage/structure/element.c:13683)() /usr/local/src/sage-4.2/local/lib/python2.6/site-packages/sage/structure/coerce.so in sage.structure.coerce.CoercionModel_cache_maps.bin_op (sage/structure/coerce.c:7021)() TypeError: unsupported operand parent(s) for '*': 'Full MatrixSpace of 2 by 2 dense matrices over Number Field in I with defining polynomial x^2 + 1' and 'Vector space of dimension 2 over Symbolic Ring' sage: regards, Jan -- .~. /V\ Jan Groenewald /( )\ www.aims.ac.za ^^-^^ -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
