cspice_vproj

 Abstract I/O Examples Particulars Required Reading Version Index_Entries

#### Abstract

```
CSPICE_VPROJ calculates the projection of a set of 3-vectors onto
another set of 3-vectors.

```

#### I/O

```
Given:

a   the vector(s) to project onto the vector(s) 'b'.

[3,n] = size(a); double = class(a)

b   the vector(s) to receive the projection(s).

[3,n] = size(b); double = class(b)

An implicit assumption exists that 'a' and 'b' are specified
in the same reference frame. If this is not the case, the numerical
result has no meaning.

the call:

vproj = cspice_vproj( a, b )

returns:

vproj   vector containing the projection(s) of 'a' onto 'b' ('vproj' is
necessarily parallel to 'b'.)  If 'b' equals the zero vector
then the zero vector will return as 'vproj'.

[3,n] = size(vproj); double = class(vproj)

'vproj' returns with the same vectorization measure, N, as
'a' and 'b'

```

#### Examples

```
Any numerical results shown for this example may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.

%
% Define two vector sets.
%
a = [ [ 6, 6, 6]', ...
[ 6, 6, 6]', ...
[ 6, 6, 0]', ...
[ 6, 0, 0]' ]

b = [ [ 2, 0, 0]', ...
[-3, 0, 0]', ...
[ 0, 7, 0]', ...
[ 0, 0, 9]' ]

%
% Calculate the projection.
%
p = cspice_vproj( a, b )

MATLAB outputs:

a =

6     6     6     6
6     6     6     0
6     6     0     0

b =

2    -3     0     0
0     0     7     0
0     0     0     9

p =

6     6     0     0
0     0     6     0
0     0     0     0

```

```
None.

```

#### Required Reading

```
For important details concerning this module's function, please refer to
the CSPICE routine vproj_c.

MICE.REQ

```

#### Version

```
-Mice Version 1.0.0, 12-MAR-2012, EDW (JPL), SCK (JPL)

```

#### Index_Entries

```
3-vector projection

```
`Wed Apr  5 18:00:36 2017`