Thanks to Henry and Raul for their solutions. I am still slightly hazy as to why one can get away with &. rather than &.: .
Henry Rich wrote: > I don't know the exact definition of n-norm I should have explained. The Lp norm of a vector v is p%:(| v)^p, an obvious case for some form of under. The L2 norm just measures the Euclidean distance of a point from the origin. You can also define the Linfinity norm of v to be the limit as p goes to infinity of Lp(v), and this has the simple form >./ | v . All of these norms are equivalent. The Linfinity is used a lot in linear algebra, since you also want matrix norms. If n is a vector norm and A is a matrix, then you can get a matrix norm by defining n(A) to be the maximum of n(Av), where n(v)=1. For the infinity norm, this is just >./ +/"1 A. The corresponding L2 norm is much more difficult to calculate. Best wishes, John ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
