# Changes between Version 1 and Version 2 of Ticket #16116

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Timestamp:
04/10/14 09:41:33 (5 years ago)
Comment:

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• ## Ticket #16116 – Description

 v1 The three matrices elmt, m and m2 are the same encoded into 3 different base rings. It would be natural to think that the cyclotomic field be the optimal field to do computations, but it does not seem to be the case in practice. Here is a univariate example where I disactivated the verification on cyclotomic fields on line 962 of the file /src/sage/matrix/matrix_space.py to get a matrix_generic_dense instead of matrix_cyclo_dense. Here is a univariate example. {{{ sage: f5=(F+~F)/2 sage: m=matrix(CF,[[-2*f5, 1, 6*f5 + 2],[-2*f5, 2*f5, 4*f5 + 1],[0,0,1]]) sage: type(m) sage: m.parent() Full MatrixSpace of 3 by 3 dense matrices over Cyclotomic Field of order 10 and degree 4 sage: %timeit m*m 100 loops, best of 3: 1.98 ms per loop }}} Then, I disactivated the verification on cyclotomic fields on line 962 of the file /src/sage/matrix/matrix_space.py to get a matrix_generic_dense instead of matrix_cyclo_dense. {{{ sage: CF.=CyclotomicField(2*5) sage: f5=(F+~F)/2 sage: m=matrix(CF,[[-2*f5, 1, 6*f5 + 2],[-2*f5, 2*f5, 4*f5 + 1],[0,0,1]]) sage: m.parent() Full MatrixSpace of 3 by 3 dense matrices over Cyclotomic Field of order 10 and degree 4