Version 5.0 The LEDA User Manual

int compare by angle(const real vector& v1 , const real vector& v2 )
For a non-zero vector v let α(v) be the angle by
which the positive x-axis has to be turned counterclockwise
until it aligns with v. The function compares
the angles defined by v1 and v2 , respectively.
The zero-vector precedes all non-zero vectors in the
angle-order.
real vector cross product(const real vector& v1 , const real vector& v2 )
4. Implementation
returns the cross product of the three-dimensional
vectors v1 and v2 .
Vectors are implemented by arrays of real numbers. All operations on a vector v take
O(v.dim()) real-number operations, except for dim and [ ] which take constant time. The
space requirement depends on the size of the representations of the coordinates.