Hi Jeff, You should make a sparse matrix by giving a dictionary of (i,j):x entries. Use a list to define a dense matrix and a dictionary to define a sparse matrix. (The error message you get below obviously sucks though, and should be fixed.)
On 4/17/07, Jeff Allotta <[EMAIL PROTECTED]> wrote: > Hi - > > How implemented is sparse linear algebra in SAGE? When I make a > MatrixSpace of sparse matrices I run into errors that don't happen > when it is dense. > > For example, creating a matrix out of a list of lists. Although, I > think I remember that this used to work a month ago -- I would just > run into problems later on. > > Thanks, > Jeff > > Here's my example code: > ************** > > [EMAIL PROTECTED]:~$ sage > ---------------------------------------------------------------------- > | SAGE Version 2.4.2, Release Date: 2007-04-12 | > | Type notebook() for the GUI, and license() for information. | > ---------------------------------------------------------------------- > > sage: relats = [[0 for i in range(10)] for j in range(10)] > sage: relats > > [[0, 0, 0, 0, 0, 0, 0, 0, 0, 0], > [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], > [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], > [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], > [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], > [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], > [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], > [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], > [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], > [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]] > > sage: B = MatrixSpace(ZZ,10,10) > sage: B > Full MatrixSpace of 10 by 10 dense matrices over Integer Ring > sage: D = MatrixSpace(ZZ,10,10,sparse=True) > sage: D > Full MatrixSpace of 10 by 10 sparse matrices over Integer Ring > sage: B(relats) > > [0 0 0 0 0 0 0 0 0 0] > [0 0 0 0 0 0 0 0 0 0] > [0 0 0 0 0 0 0 0 0 0] > [0 0 0 0 0 0 0 0 0 0] > [0 0 0 0 0 0 0 0 0 0] > [0 0 0 0 0 0 0 0 0 0] > [0 0 0 0 0 0 0 0 0 0] > [0 0 0 0 0 0 0 0 0 0] > [0 0 0 0 0 0 0 0 0 0] > [0 0 0 0 0 0 0 0 0 0] > > sage: D(relats) > --------------------------------------------------------------------------- > <type 'exceptions.TypeError'> Traceback (most recent call > last) > > /home/jallotta/<ipython console> in <module>() > > /home/was/s/local/lib/python2.5/site-packages/sage/matrix/matrix_space.py > in __call__(self, entries, coerce, copy) > 261 elif > sage.groups.matrix_gps.matrix_group_element.is_MatrixGroupElement(entries): > 262 return self(entries.matrix(), copy=False) > --> 263 return self.matrix(entries, copy=copy, coerce=coerce) > 264 > 265 def change_ring(self, R): > > /home/was/s/local/lib/python2.5/site-packages/sage/matrix/matrix_space.py > in matrix(self, x, coerce, copy) > 619 elif isinstance(x[0], tuple): > 620 x = list(sum(x,())) > --> 621 return self.__matrix_class(self, entries=x, copy=copy, > coerce=coerce) > 622 > 623 def matrix_space(self, nrows=None, ncols=None, > sparse=False): > > /home/jallotta/matrix_integer_sparse.pyx in > matrix_integer_sparse.Matrix_integer_sparse.__init__() > > /home/jallotta/integer_ring.pyx in > integer_ring.IntegerRing_class.__call__() > > <type 'exceptions.TypeError'>: unable to coerce element to an integer > > -- William Stein Associate Professor of Mathematics University of Washington http://www.williamstein.org --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@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-support URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
