Name

---

  UNITIZE

Author

---

  Craig B. Markwardt, NASA/GSFC Code 662, Greenbelt, MD 20770
  [email protected]
  UPDATED VERSIONs can be found on my WEB PAGE:
      http://cow.physics.wisc.edu/~craigm/idl/idl.html

Purpose

---

  Construct a unit vector from a vector

Major Topics

---

  Geometry

Calling Sequence

---

  U = UNITIZE(V)

Description

---

  The function UNITIZE accepts any vector as input, and returns a
  unit vector. The returned vector has the same direction as V but
  a unit magnitude. (using L2 norm)
  Mostly commonly UNITIZE will be used on 3-vectors. The input V
  may either be a single 3-vector (i.e. DBLARR(3)) or it may be an
  array of N 3-vectors, (i.e. DBLARR(3,N)). The returned array will
  have the same structure as V.
  UNITIZE also works on vectors with arbitrary numbers of
  components. All that is required is that the vector components be
  the first dimension of the input array V.

Inputs

---

  V - input array, commonly a 3-vector for a single vector, or a 3xN
      array for N vectors. It is also possible to pass any array
      DBLARR(M,n1,n2,n3,...).

Returns

---

  The resulting unitized vector or vectors. The output has the same
  dimension as the input, V.

Keyword Parameters

---

  NONE

Example

---

  print, unitize([3d,4d,0d])
    ==> [0.6, 0.8, 0.0]

See Also

---

  UNITVECANG, ANGUNITVEC, CROSSP, QTNORMALIZE

Modification History

---

  Written, 1999, CM
  Converted to more general dimension, 2012-10-02, CM
  Documented, 2012-10-02, CM
  $Id: unitize.pro,v 1.5 2012/10/02 12:28:47 cmarkwar Exp $