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vperp_c

 Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input Detailed_Output Parameters Exceptions Files Particulars Examples Restrictions Literature_References Author_and_Institution Version Index_Entries

Procedure

```   vperp_c ( Perpendicular component of a 3-vector )

void vperp_c ( ConstSpiceDouble   a[3],
ConstSpiceDouble   b[3],
SpiceDouble        p[3] )

```

Abstract

```   Find the component of a vector that is perpendicular to a second
vector. All vectors are 3-dimensional.
```

```   None.
```

Keywords

```   VECTOR

```

Brief_I/O

```   VARIABLE  I/O  DESCRIPTION
--------  ---  --------------------------------------------------
a          I   The vector whose orthogonal component is sought.
b          I   The vector used as the orthogonal reference.
p          O   The component of `a' orthogonal to `b'.
```

Detailed_Input

```   a           is a double precision, 3-dimensional vector. It the
vector whose component orthogonal to `b' is sought. (There
is a unique decomposition of `a' into a sum v + p, where `v'
is parallel to `b' and `p' is orthogonal to `b'. We want the
component `p'.)

b           is a double precision, 3-dimensional vector. This
vector is the vector used as a reference for the
decomposition of `a'.
```

Detailed_Output

```   p           is a double precision, 3-dimensional vector containing
the component of `a' that is orthogonal to `b'.
`p' may overwrite either `a' or `b'.
```

Parameters

```   None.
```

Exceptions

```   Error free.
```

Files

```   None.
```

Particulars

```   Given and non-zero vector `b' and a vector `a', there is a unique
decomposition of `a' as a sum v + p such that `p' is orthogonal
to `b' and `v' is parallel to `b'. This routine finds the vector `p'.

If `b' is a zero vector, `p' will be identical to `a'.
```

Examples

```   The following table gives sample inputs and results from calling
vperp_c.

a                  b                 p
------------------------------------------
(6, 6, 6)      ( 2, 0, 0)        (0, 6, 6)
(6, 6, 6)      (-3, 0, 0)        (0, 6, 6)
(6, 6, 0)      ( 0, 7, 0)        (6, 0, 0)
(6, 0, 0)      ( 0, 0, 9)        (6, 0, 0)
```

Restrictions

```   None.
```

Literature_References

```   [1]  G. Thomas and R. Finney, "Calculus and Analytic Geometry,"
```

Author_and_Institution

```   N.J. Bachman        (JPL)
J. Diaz del Rio     (ODC Space)
W.L. Taber          (JPL)
E.D. Wright         (JPL)
```

Version

```   -CSPICE Version 1.2.2, 13-APR-2021 (JDR)

Updated the header to comply with NAIF standard.

-CSPICE Version 1.2.1, 24-APR-2010 (EDW)

Minor edit to code comments eliminating typo.

-CSPICE Version 1.2.0, 22-OCT-1998 (NJB)

```   perpendicular component of a 3-vector
`Fri Dec 31 18:41:15 2021`