VEC_$IMULT_SUB_VECTOR16           Domain/OS            VEC_$IMULT_SUB_VECTOR16


NAME
     vec_$imult_sub_vector16 - multiply two 16-bit integer vectors, subtract a
     third

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

     void vec_$imult_sub_vector16(
          short int *start_vec,
          short int *mult_vec,
          short int *sub_vec,
          long int &length,
          short int *result_vec)

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

     procedure vec_$imult_sub_vector16(
          in start_vec: univ vec_$integer16_vector;
          in mult_vec: univ vec_$integer16_vector;
          in sub_vec: univ vec_$integer16_vector;
          in length: integer32;
          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 start_vec(nvec), result_vec(nvec), mult_vec(nvec), sub_vec(nvec)
           integer*4 length

           call vec_$imult_sub_vector16(start_vec, mult_vec, sub_vec, length, result_vec)

DESCRIPTION
     Vec_$imult_sub_vector16 multiplies the vector start_vec by mult_vec, sub-
     tracts sub_vec from the result, and stores the final result in
     result_vec.  It differs from vec_$mult_sub_vector in that the vectors
     being handled contain 32-bit integers.  The calculation performed is as
     follows:

     For each integer I such that 1 <= I <= length,
     result_vec(I) = (start_vec(I) x mult_vec(I)) - sub_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.

     start_vec
          A multiplicand vector.

     mult_vec
          A multiplicand vector.

     sub_vec
          A vector to be subtracted.

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

     result_vec
          The vector created by multiplying mult_vec and start_vec and sub-
          tracting sub_vec from the result.

NOTES
     When vec_$imult_sub_vector16 is used to operate on matrixes in C and Pas-
     cal, start_vec, sub_vec, mult_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
     contain any subset of it.   Because of pipelining, using overlapping
     input and output arrays may cause incorrect results.

     Vec_$imult_sub_vector16, like all 16-bit integer routines, performs
     poorly when compared to the 32-bit integer routines.  Its use should be
     avoided wherever possible, especially on high-performance workstations.

SEE ALSO
     vec_$add_mult_vector, vec_$sub_mult_vector, vec_$mult_add_vector,
     vec_$mult_rsub_vector, vec_$add_add_vector, vec_$sub_add_vector,
     vec_$mult_mult_vector, vec_$mult_sub_vector, vec_$mult_sub_vector_i,
     vec_$dmult_sub_vector, vec_$dmult_sub_vector_i, vec_$imult_sub_vector,
     vec_$imult_sub_vector_i, vec_$imult_sub_vector16_i.