This is misleading even if not strictly incorrect. In matrix terminology, outer product is definitely more commonly used.
On Sun, Dec 25, 2011 at 1:37 PM, Dmitriy Lyubimov <[email protected]> wrote: > Hello, > > just stumbled on this in vector while looking for outer product operation > -- > > @Override > public Matrix cross(Vector other) { > Matrix result = matrixLike(size, other.size()); > for (int row = 0; row < size; row++) { > result.assignRow(row, other.times(getQuick(row))); > } > return result; > } > > > It seems this guy computes an outer product, but not cross product ( > crossprod for vectors =ab sin(theta)n). Seems like a misleading > naming. > > It is probably motivated by R, where tcrossproduct (which is a product > of matrices, not vectors) is defined as XY' and crossprod which is > defined X'Y and so in case of cbind(vector) it would constitute either > dot product or outer product respectively. But i am not sure where R > is deriving this; and even then it is definitely misleading as R would > apply this to the world of matrices, not vectors. In vectors cross > product means something else and i think this may create a confusion > (it certainly did in my case).. > > thanks. > -Dmitriy >
