Procedure

     VMINUG ( Negate vector, "-V", general dimension )

     SUBROUTINE VMINUG ( VIN, NDIM, VOUT )

Abstract

     Negate a double precision vector of arbitrary dimension.

Required_Reading

     None.

Keywords

     VECTOR

Declarations

     IMPLICIT NONE

     INTEGER            NDIM
     DOUBLE PRECISION   VIN   ( NDIM )
     DOUBLE PRECISION   VOUT  ( NDIM )

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     VIN        I   n-dimensional vector to be negated.
     NDIM       I   Dimension of VIN (and also VOUT).
     VOUT       O   Negated vector -V1.

Detailed_Input

     VIN      is any double precision vector of arbitrary size.

     NDIM     is the dimension of VIN and VOUT.

Detailed_Output

     VOUT     is a n-dimensional double precision vector which
              contains the negation of VIN.

Parameters

     None.

Exceptions

     Error free.

Files

     None.

Particulars

     For each value of the index I from 1 to NDIM, VMINUG negates VIN
     by the expression:

        VOUT(I) = - VIN(I)

     No error checking is performed since overflow can occur ONLY if
     the dynamic range of positive floating point numbers is not the
     same size as the dynamic range of negative floating point numbers
     AND at least one component of VIN falls outside the common range.
     The likelihood of this occurring is so small as to be of no
     concern.

Examples

     The numerical results shown for this example may differ across
     platforms. The results depend on the SPICE kernels used as
     input, the compiler and supporting libraries, and the machine
     specific arithmetic implementation.

     1) Define a set of n-dimensional vectors and negate each of them.


        Example code begins here.


              PROGRAM VMINUG_EX1
              IMPLICIT NONE

        C
        C     Local parameters.
        C
              INTEGER               NDIM
              PARAMETER           ( NDIM   = 4 )

              INTEGER               SETSIZ
              PARAMETER           ( SETSIZ = 2 )

        C
        C     Local variables.
        C
              DOUBLE PRECISION      VIN  ( NDIM, SETSIZ )
              DOUBLE PRECISION      VOUT ( NDIM         )

              INTEGER               I
              INTEGER               J

        C
        C     Define a set of n-dimensional vectors.
        C
              DATA                  VIN  /
             .                    -10.D0, 15.D0, -5.D0, 20.D0,
             .                      0.D0,  0.D0,  0.D0,  0.D0  /

        C
        C     Negate each vector
        C
              DO I=1, SETSIZ

                 CALL VMINUG ( VIN(1,I), NDIM, VOUT )

                 WRITE(*,'(A,4F7.1)') 'Input vector  : ',
             .                        ( VIN(J,I), J=1,NDIM )
                 WRITE(*,'(A,4F7.1)') 'Negated vector: ', VOUT
                 WRITE(*,*)

              END DO

              END


        When this program was executed on a Mac/Intel/gfortran/64-bit
        platform, the output was:


        Input vector  :   -10.0   15.0   -5.0   20.0
        Negated vector:    10.0  -15.0    5.0  -20.0

        Input vector  :     0.0    0.0    0.0    0.0
        Negated vector:    -0.0   -0.0   -0.0   -0.0

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     N.J. Bachman       (JPL)
     J. Diaz del Rio    (ODC Space)
     W.M. Owen          (JPL)
     W.L. Taber         (JPL)

Version

    SPICELIB Version 1.0.3, 02-OCT-2020 (JDR)

        Added IMPLICIT NONE statement.

        Edited the header to comply with NAIF standard. Added complete
        code example based on existing example.

        Extended $Particulars section.

    SPICELIB Version 1.0.2, 23-APR-2010 (NJB)

        Header correction: assertions that the output
        can overwrite the input have been removed.

    SPICELIB Version 1.0.1, 10-MAR-1992 (WLT)

        Comment section for permuted index source lines was added
        following the header.

    SPICELIB Version 1.0.0, 31-JAN-1990 (WMO)