On Thu, Apr 18, 2013 at 5:42 PM, Juan Grados <juan...@gmail.com> wrote:
> I ask this because I am study McEliece Cryptosystem. And to get > the generator matrix of Goppa code I am using the right_kernel() > instruction > > Krnl = H.right_kernel(); > > but I get always these form. The parity check matrix is building using the > matrix > T, V and D. How I will be able to get generator matrix in other form? > I might be misunderstanding you but does standard_form in linear_code help? https://github.com/sagemath/sagelib/blob/master/sage/coding/linear_code.py > > > > H: is a parity check matrix. > T: Toepliz > V: Vandermonde > D: Diagonal > > > 2013/4/18 William Stein <wst...@gmail.com> > >> On Thu, Apr 18, 2013 at 1:50 PM, Juan Grados <juan...@gmail.com> wrote: >> > Dears members, >> > >> > I executed right_kernel() for any matrix H. Why always I get a basis >> matrix >> > in this form [I|A] (I:identity)? >> >> That's not true for the 1x2 matrix [1,0]: >> >> sage: matrix(1,2,[1,0]).right_kernel() >> Free module of degree 2 and rank 1 over Integer Ring >> Echelon basis matrix: >> [0 1] >> >> The basis matrix is not of the form [I|A], for I the identity matrix. >> >> For a *random* matrix you'll get [I|A] though. >> >> William >> >> William >> >> >> >> > >> > -- >> > --------------------------------------------------------------------- >> > MSc. Juan del Carmen Grados Vásquez >> > Laboratório Nacional de Computação Científica >> > Tel: +55 24 2233-6260 >> > (http://www.lncc.br/) >> > http://juaninf.blogspot.com >> > --------------------------------------------------------------------- >> > >> > -- >> > You received this message because you are subscribed to the Google >> Groups >> > "sage-support" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> an >> > email to sage-support+unsubscr...@googlegroups.com. >> > To post to this group, send email to sage-support@googlegroups.com. >> > Visit this group at http://groups.google.com/group/sage-support?hl=en. >> > For more options, visit https://groups.google.com/groups/opt_out. >> > >> > >> >> >> >> -- >> William Stein >> Professor of Mathematics >> University of Washington >> http://wstein.org >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sage-support" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to sage-support+unsubscr...@googlegroups.com. >> To post to this group, send email to sage-support@googlegroups.com. >> Visit this group at http://groups.google.com/group/sage-support?hl=en. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > > -- > --------------------------------------------------------------------- > MSc. Juan del Carmen Grados Vásquez > Laboratório Nacional de Computação Científica > Tel: +55 24 2233-6260 > (http://www.lncc.br/) > http://juaninf.blogspot.com > --------------------------------------------------------------------- > > -- > You received this message because you are subscribed to the Google Groups > "sage-support" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-support+unsubscr...@googlegroups.com. > To post to this group, send email to sage-support@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-support?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
