Seems like the cost of doing business, the entries of U are pretty big: sage: print(RR(log(abs(U[0][0]),2))) 1277.66401749439
Santanu Sarkar <sarkar.santanu....@gmail.com> writes: > Dear Martin, > Kindly see the following code. > > from fpylll import (IntegerMatrix, LLL) > row=160 > col=100 > tt=cputime() > A = random_matrix(ZZ, row,col,x=-2000, y=2000) > U = IntegerMatrix.identity(row) > tt=cputime() > B = LLL.reduction(IntegerMatrix.from_matrix(A), U).to_matrix(matrix(ZZ, > row,col)) > print cputime(tt) > tt=cputime() > A=A.LLL() > print cputime(tt) > > Lattice reduction takes 49 seconds in the first case and 7 seconds in the > second case. > Maybe I am missing something. > > Best regards, > Santanu > > On Tue, 29 Sep 2020 at 09:01, 'Martin R. Albrecht' via sage-devel < > sage-devel@googlegroups.com> wrote: > >> Hi there, >> >> Sage is using FP(y)LLL under the hood, so there shouldn’t be that much of >> a performance difference. As far as I can see, both Sage and FPyLLL have >> the same defaults so it’s not clear to me why you see this performance >> difference. >> >> Cheers, >> Martin >> >> >> Santanu Sarkar <sarkar.santanu....@gmail.com> writes: >> > Dear Martin, >> > Thank you so much. It works! >> > Can we make it faster? >> > It took 17 seconds for my problem but >> > M1.LLL() took only 3 seconds. Of course I understand we >> > are calculating extra matrix U. >> > >> > Thanks again for your help. >> > >> > Regards, >> > Santanu >> > >> > >> > >> > On Sun, 27 Sep 2020 at 20:45, 'Martin R. Albrecht' via sage-devel < >> > sage-devel@googlegroups.com> wrote: >> > >> >> Hi there, >> >> >> >> This should do the trick: >> >> >> >> sage: from fpylll import * >> >> sage: A = random_matrix(ZZ, 6, 90) >> >> sage: U = IntegerMatrix.identity(6) >> >> sage: B = LLL.reduction(IntegerMatrix.from_matrix(A), >> >> U).to_matrix(matrix(ZZ, 6, >> >> 90)) >> >> sage: U = U.to_matrix(matrix(ZZ, 6,6)) >> >> sage: B == U*A >> >> True >> >> sage: abs(U.det()) >> >> 1 >> >> >> >> Cheers, >> >> Martin >> >> >> >> >> >> Santanu Sarkar <sarkar.santanu....@gmail.com> writes: >> >> > Dear all, >> >> > I have a matrix M1 with integer entries with 90 rows and 6 columns. >> >> > After applying LLL algorithm of M1, I get M2=M1.LLL(). I want to get >> >> > corresponding unimodular transformation matrix T such that >> >> > T*M1=M2. We can find T by >> >> > T=M2*M1.pseudoinverse() or T== M1.solve_left(M2), but determinant of T >> >> > becomes 0 i.e., T.det()=0. >> >> > I want T.det()=1. >> >> > >> >> > Best regards, >> >> > Santanu >> >> >> >> >> >> -- >> >> >> >> _pgp: https://keybase.io/martinralbrecht >> >> _www: https://malb.io >> >> >> >> -- >> >> 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 sage-devel+unsubscr...@googlegroups.com. >> >> To view this discussion on the web visit >> >> >> https://groups.google.com/d/msgid/sage-devel/87h7rjmesx.fsf%40googlemail.com >> >> . >> >> >> >> >> -- >> >> _pgp: https://keybase.io/martinralbrecht >> _www: https://malb.io >> >> -- >> 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 sage-devel+unsubscr...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sage-devel/87blhrm5uu.fsf%40googlemail.com >> . >> -- _pgp: https://keybase.io/martinralbrecht _www: https://malb.io -- 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 sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/874knfe0py.fsf%40googlemail.com.
