On 27.02.19 15:35, Dima Pasechnik wrote: >> Yes, this is the interesting case. The problem then is going back from >> the projection. I guess that orthogonality is ususally destroyed here... > One can ensure it is orthonormal: > > sage: P = polytopes.simplex(2) > sage: > M=P.affine_hull(orthonormal=True,as_affine_map=True,extend=True)[0].matrix() > sage: v=P.inequalities()[0].vector()[1:] > sage: M*(v*M) > (0.6666666666666667?, -0.3333333333333334?, -0.3333333333333334?) > sage: v=P.inequalities()[1].vector()[1:] > sage: M*(v*M) > (-0.3333333333333334?, 0.6666666666666667?, -0.3333333333333334?) > sage: v=P.inequalities()[2].vector()[1:] > sage: M*(v*M) > (-0.3333333333333334?, -0.3333333333333334?, 0.6666666666666667?) > > So you get your normal vectors in the subspace parallel to the affine hull of > P.
Thank you, looks easy :) (I am now just using orthogonal=True in my case, as I do not want to get non-rational.) Daniel -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
