On Wednesday, December 5, 2012 1:56:55 PM UTC, Jason Grout wrote: > > On 12/5/12 7:46 AM, John Cremona wrote: > > I don't know why this takes so long: > > > > I have a field F (a snumber field of high degree, 288 in fact) and > > want to create a 100x100 matrix over F from a list of 100 lists of 100 > > elements of F, while I will call "entries". If I do > > > > M = Matrix(entries) > > > > which certainly works fine with smaller examples, then I get tired of > > waiting (after 10 or 15 minutes) and cannot even interrupt with > > Ctrl-C. But if I do > > > > M = copy(MatrixSpace(F,100).zero_matrix()) > > for i in range(100): > > for j in range(100): > > M[i,j] = entries[i,j] > > > > it works in a few seconds. So what is going wrong with the first > (simpler) way? > > If you just do Matrix(entries), it tries to guess the right base ring > (using the Sequence() command, IIRC). In the second example, you are > explicitly telling Sage the base ring. I wonder if that is what is > going on. To check, can you try doing: > > matrix(F, entries) > > That is slow too. Try
Q1092.<z>=CyclotomicField(1092) entries = [[Q1092.zero_element() for i in range(100)] for j in range(100)] M=Matrix(Q1092,entries) which takes a long time (*) and cannot be interrupted with Ctrl-C. John (*) I have not yet had the patience to wait until it completes! > Thanks, > > Jason > > > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support?hl=en.
