VEC_$IMULT_ADD16                  Domain/OS                   VEC_$IMULT_ADD16


NAME
     vec_$imult_add16 - multiply a scalar by a 16-bit integer vector, add a
     vector

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

     void vec_$imult_add16(
          short int *add_vec,
          short int *mult_vec,
          long int &length,
          short int &constant,
          short int *result_vec)

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

     procedure vec_$imult_add16(
          in add_vec: univ vec_$integer16_vector;
          in mult_vec: univ vec_$integer16_vector;
          in length: integer32;
          in constant: integer16;
          out result_vec: univ vec_$integer16_vector);

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

           parameter (nvec = 10)

           integer*2 add_vec(nvec), mult_vec(nvec), result_vec(nvec), constant
           integer*4 length

           call vec_$imult_add16(add_vec, mult_vec, length, constant, result_vec)

DESCRIPTION
     Vec_$imult_add16 multiplies the vector mult_vec by the scalar constant,
     adds the result to the vector add_vec, and stores the result in
     result_vec.  It differs from vec_$mult_add in that the vectors being han-
     dled contain 16-bit integers.  The calculation performed is as follows:

     For each integer I such that 1 <= I <= length,
     result_vec(I) = (constant x mult_vec(I)) + add_vec(I)

     Note that the multiplication done by this call is point-wise.  This call
     does not perform matrix multiplication, since the product of two vectors
     is another vector of the same magnitude.

     add_vec
          The vector to be added.

     mult_vec
          The vector to be multiplied.

     length
          The number of elements to be operated on;  normally the same as the
          number of elements in the vectors.

     constant
          The scalar by which mult_vec is multiplied.

     result_vec
          The vector created by multiplying mult_vec by constant and adding
          add_vec to the result.

NOTES
     When vec_$imult_add16 is used to operate on matrixes in C and Pascal,
     mult_vec, add_vec, and result_vec are row vectors; in FORTRAN, they are
     column vectors.

     As in all the vec_$ calls, the result array must not overlap any of the
     input arrays; the result array may be identical to an input, but must not
     conatain any subset of it.   Because of pipelining, using overlapping
     input and output arrays may cause incorrect results.

     Vec_$imult_add16, like all 16-bit integer routines, performs poorly when
     compared to the 32-bit integer routines.  Its use should be avoided wher-
     ever possible, especially on high-performance workstations.

SEE ALSO
     vec_$mult_add, vec_$add_mult, vec_$sub_mult, vec_$mult_sub,
     vec_$mult_add_i, vec_$dmult_add, vec_$dmult_add_i, vec_$imult_add,
     vec_$imult_add_i, vec_$imult_add16_i.