Your matrix easily exceeds the precision limit if the determinant is computed naively.
sage: A.change_ring(RealIntervalField(53)).det() 0.?e10 sage: A.change_ring(RealIntervalField(60)).det() 0.?e8 sage: A.change_ring(RealIntervalField(80)).det() 1.68?e4 sage: A.change_ring(RealIntervalField(100)).det() 16801.79800? B turns out to be correct since it uses a numerically more stable algorithm. As a rule of thumb, computations with hardware floating point numbers tend to be implemented best (at the cost of supporting only a singe choice for precision) On Monday, January 20, 2014 4:28:45 PM UTC, P Purkayastha wrote: > > Which of these outputs should we trust? > > In the face of numerical instability you should trust neither ;-) -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
