On Tue, Jun 2, 2009 at 8:45 PM, davidp <[email protected]> wrote: > > I can't figure out how to create a new sparse matrix (see below). > > Sorry, > Dave
You can make a new matrix with the analogous parent but a different shape using the new_matrix method. sage: a = random_matrix(ZZ,3,4,sparse=True) sage: a.new_matrix(2,4) [0 0 0 0] [0 0 0 0] In your cython code you would write something like cdef Matrix_integer_sparse M = a.new_matrix(2,4) William > > M = Matrix_integer_sparse.__new__(Matrix_integer_sparse, > sage.matrix.matrix_space.MatrixSpace(ZZ, self._nrows-1, self._ncols, > sparse=True), None, None, None) > > > ------------------- > ... > def _delete_row_(self, Py_ssize_t row_number): > cdef Py_ssize_t i > cdef mpz_vector* self_row, *M_row > cdef Matrix_integer_sparse M > > M = Matrix_integer_sparse.__new__(Matrix_integer_sparse, > sage.matrix.matrix_space.MatrixSpace(ZZ, self._nrows-1, self._ncols, > sparse=True), None, None, None) > > ^ > ------------------------------------------------------------ > > /usr/local/sage-devel/devel/sage-devel/sage/matrix/ > matrix_integer_sparse.pyx:221:101: Compiler crash in > AnalyseExpressionsTransform > > ModuleNode.body = StatListNode(matrix_integer_sparse.pyx:23:0) > StatListNode.stats[13] = StatListNode(matrix_integer_sparse.pyx:43:5) > StatListNode.stats[0] = CClassDefNode(matrix_integer_sparse.pyx:43:5, > as_name = u'Matrix_integer_sparse', > base_class_module = u'matrix_sparse', > base_class_name = u'Matrix_sparse', > class_name = u'Matrix_integer_sparse', > module_name = '', > visibility = 'private') > CClassDefNode.body = StatListNode(matrix_integer_sparse.pyx:55:4) > StatListNode.stats[9] = DefNode(matrix_integer_sparse.pyx:216:4, > name = u'_delete_row_', > num_required_args = 2, > reqd_kw_flags_cname = '0') > File 'Nodes.py', line 360, in analyse_expressions: StatListNode > (matrix_integer_sparse.pyx:217:8) > File 'Nodes.py', line 2835, in analyse_expressions: > SingleAssignmentNode(matrix_integer_sparse.pyx:221:41) > File 'Nodes.py', line 2928, in analyse_types: SingleAssignmentNode > (matrix_integer_sparse.pyx:221:41) > File 'ExprNodes.py', line 2281, in analyse_types: SimpleCallNode > (matrix_integer_sparse.pyx:221:41) > File 'ExprNodes.py', line 3105, in analyse_types: TupleNode > (matrix_integer_sparse.pyx:221:41, > is_sequence_constructor = 1) > File 'ExprNodes.py', line 2972, in analyse_types: TupleNode > (matrix_integer_sparse.pyx:221:41, > is_sequence_constructor = 1) > File 'ExprNodes.py', line 2522, in analyse_types: GeneralCallNode > (matrix_integer_sparse.pyx:221:101) > > Compiler crash traceback from this point on: > File "/usr/local/sage-devel/local/lib/python2.5/site-packages/Cython/ > Compiler/ExprNodes.py", line 2532, in analyse_types > if hasattr(self.function, 'entry') and not > self.function.entry.as_variable: > AttributeError: 'NoneType' object has no attribute 'as_variable' > Error running command, failed with status 256. > sage: There was an error installing modified sage library code. > > > On Jun 2, 7:28 pm, William Stein <[email protected]> wrote: >> On Tue, Jun 2, 2009 at 7:22 PM, davidp <[email protected]> wrote: >> >> > I tried adding a delete_row method to matrix_integer_sparse.pyx but >> > stopped after getting the error message: >> >> Just def your method -- do not cpdef it. You can still use Cython >> code in a cpdef's method and it will be just as fast. >> >> Make sure that your "delete row" method returns a *new* matrix by the way... >> >> William >> >> >> >> >> >> > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> > Error converting Pyrex file to C: >> > ------------------------------------------------------------ >> > ... >> > add_mpz_vector_init(&M._matrix[i], &self._matrix[i], & >> > (<Matrix_integer_sparse>right)._matrix[i], mul) >> > mpz_clear(mul) >> > return M >> >> > # added by David Perkinson >> > cpdef ModuleElement _delete_row_(self, Py_ssize_t row_number): >> > ^ >> > ------------------------------------------------------------ >> >> > /usr/local/sage-devel/devel/sage-devel/sage/matrix/ >> > matrix_integer_sparse.pyx:216:10: C method '_delete_row_' not >> > previously declared in definition part of extension type >> > Error running command, failed with status 256. >> > sage: There was an error installing modified sage library code. >> >> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> > I might have to actually read the Cython documentation! >> >> > Dave >> >> > On Jun 2, 5:43 pm, Jason Grout <[email protected]> wrote: >> >> William Stein wrote: >> >> > On Mon, Jun 1, 2009 at 5:16 PM, davidp <[email protected]> wrote: >> >> >> Is there a fast way to create a submatrix? >> >> >> >> ------------------------------------------------- >> >> >> >> sage: version() >> >> >> 'Sage Version 4.0.alpha0, Release Date: 2009-05-15' >> >> >> sage: G = graphs.GridGraph([100,100]) >> >> >> sage: L = G.laplacian_matrix() >> >> >> sage: L >> >> >> 10000 x 10000 sparse matrix over Integer Ring >> >> >> sage: time M = L[1:9999,1:9999] >> >> >> CPU times: user 24.93 s, sys: 0.04 s, total: 24.97 s >> >> >> Wall time: 25.27 s >> >> >> >> ---------------------------------------------------- >> >> >> >> I am just interested in deleting a single row and column of the matrix >> >> >> (not necessarily the first). >> >> >> >> Thanks, >> >> >> > There is no fast way to do that right now. One could easily add code >> >> > to SAGE_ROOT/devel/sage/sage/matrix/matrix_integer_sparse.pyx that >> >> > would provide blazingly fast deletion of a row, and reasonably fast >> >> > deletion of a column. Of course it would be better to implement >> >> > arbitrary slicing in some optimized way in matrix_integer_sparse.pyx. >> >> > I hope somebody does so. >> >> >> Just looking at the generic code, it seems that it goes through each and >> >> every index position in the slice, setting the new matrix entry to the >> >> old one. This is obviously the wrong thing to do for sparse matrices, >> >> and can likely trivially be made faster. I think all you may have to do >> >> is override the matrix_from_rows_and_columns for sparse matrices. >> >> >> Jason >> >> -- >> William Stein >> Associate Professor of Mathematics >> University of Washingtonhttp://wstein.org > > > -- William Stein Associate Professor of Mathematics University of Washington http://wstein.org --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] 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://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
