CROSSPN Name
CROSSPN
Author
Craig B. Markwardt, NASA/GSFC Code 662, Greenbelt, MD 20770
craigm@lheamail.gsfc.nasa.gov Purpose
A version of CROSSP for efficient vector cross products
Calling Sequence
C = CROSSPN(A, B)
Description
The function CROSSPN computes the vector cross product (outer
product). The difference between CROSSPN and the IDL library
function CROSSP, is that CROSSPN allows more than one cross
product to be computed at one time (i.e., it is vectorized).
Thus, in the expression "C = CROSSPN(A, B)" the vector cross
product is computed as C = A x B. Because CROSSPN is vectorized,
any of the following combinations are valid:
* A is a 3-vector, B is a 3-vector
==> C is the vector cross product C = A x B
* A is a 3xN array, B is a 3-vector
==> C(*,I) = A(*,I) x B (each A is crossed with B)
* A is a 3-vector, B is a 3xN array
==> C(*,I) = A x B(*,I) (A is crossed with each B)
* A is a 3xN array, B is a 3xN array
==> C(*,I) = A(*,I) x B(*,I) (component-by-component)
If both A and B are arrays then they must have the same
dimensions. Inputs
A - a 3-vector or 3xN array.
B - a 3-vector or 3xN array.
Returns
The vector cross product A x B, either a 3-vector or a 3xN array
depending on A and B. See Also
CROSSP Modification History
Written, CM, 10 Mar 2002
Documented, CM, 22 Mar 2002