vec_dsum() — Apollo

VEC_$DSUM                         Domain/OS                          VEC_$DSUM


NAME
     vec_$dsum - sum the elements of a double-precision vector

SYNOPSIS (C)
     #include <apollo/base.h>
     #include <apollo/vec.h>

     double vec_$dsum(
          double *vec,
          long int &length)

SYNOPSIS (Pascal)
     %include '/sys/ins/base.ins.pas';
     %include '/sys/ins/vec.ins.pas';

     function vec_$dsum(
          in vec: univ vec_$double_vector;
          in length: integer32): double;

SYNOPSIS (FORTRAN)
     %include '/sys/ins/base.ins.ftn'
     %include '/sys/ins/vec.ins.ftn'

           parameter (nvec = 10)

           double precision vec(nvec), sum
           integer*4 length

           sum = vec_$dsum(vec, length)

DESCRIPTION
     Vec_$dsum adds together length elements of the double-precision array
     vector and returns the sum.

     In C, the resulting operation is

          return_value = 0.0;
          for (i = 0; i < length; ++i)
               return_value += vec[i];

     In Pascal, the resulting operation is

          return_value := 0.0;
          for i := 1 to length do
               return_value := return_value + vec[i];

     In FORTRAN, the resulting operation is

           vec_$dsum = 0.0
           do 10 i = 1, length
               vec_$dsum = vec_$dsum + vec(i)
       10  continue

     vec  The vector to sum.

     length
          The number of elements in vec to sum.

NOTES
     When vec_$dsum is used to operate on matrixes in C and Pascal, vec is a
     row vector; whereas in FORTRAN, it is a column vector.

SEE ALSO
     vec_$dsum_i, vec_$isum, vec_$isum16, vec_$sum.
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