void vhatg_c ( ConstSpiceDouble * v1,
SpiceInt ndim,
SpiceDouble * vout )
Find the unit vector along a double precision vector of
arbitrary dimension.
None.
VECTOR
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
v1 I Vector to be normalized.
ndim I Dimension of v1 (and also vout).
vout O Unit vector v1 / |v1|.
If v1 = 0, vout will also be zero.
vout can overwrite v1.
v1 This is any double precision vector of arbitrary
dimension. This routine will detect if is V1 the
zero vector, and will not attempt to divide by zero.
ndim is the dimension of V1 (and also VOUT).
vout contains the unit vector in the direction of v1. If
v1 represents the zero vector, then vout will also be
the zero vector. vout may overwrite v1.
None.
Error free.
None.
vhatg_c determines the magnitude of V1 and then divides each
component of V1 by the magnitude. This process is highly stable
over the whole range of multi-dimensional vectors.
The following table shows how selected v1 maps to vout.
v1 ndim vout
-----------------------------------------------------------------
(5, 12, 0, 0) 4 (5/13, 12/13, 0, 0)
(1e-7, 2D-e, 2e-7) 3 (1/3, 2/3, 2/3)
The relative number of cases whereby floating point overflow may
occur is negligible. Thus, no error recovery or reporting scheme
is incorporated into this subroutine.
None.
N.J. Bachman (JPL)
W.M. Owen (JPL)
-CSPICE Version 1.0.0, 13-JUL-1999 (NJB) (WMO)
unitize a n-dimensional vector
Link to routine vhatg_c source file vhatg_c.c
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