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VEC_$MULT_MULT_VECTOR_I           Domain/OS            VEC_$MULT_MULT_VECTOR_I


NAME
     vec_$mult_mult_vector_i - multiply three single-precision vectors

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

     void vec_$mult_mult_vector_i(
          float *start_vec,
          long int &start_inc,
          float *mult_vec,
          long int &mult_inc,
          float *mult_vec_2,
          long int &mult_inc_2,
          long int &length,
          float *result_vec,
          long int &result_inc)

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

     procedure vec_$mult_mult_vector_i(
          in start_vec: univ vec_$real_vector;
          in start_inc: integer32;
          in mult_vec: univ vec_$real_vector;
          in mult_inc: integer32;
          in mult_vec_2: univ vec_$real_vector;
          in mult_inc_2: integer32;
          in length: integer32;
          out result_vec: univ vec_$real_vector;
          in result_inc: integer32);

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

           parameter (nvec = 10)

           real start_vec(nvec), result_vec(nvec), mult_vec(nvec), mult_vec_2(nvec)
           integer*4 length
           integer*4 start_inc, mult_inc, mult_inc_2, result_inc

           call vec_$mult_mult_vector_i(start_vec, start_inc, mult_vec, mult_inc,
          & mult_vec_2, mult_inc_2, length, result_vec, result_inc)

DESCRIPTION
     Vec_$mult_mult_vector_i multiplies the vectors start_vec and  mult_vec,
     multiplies the result by mult_vec_2, and stores the final result in
     result_vec.

     This call, like all vec_$ calls ending in _i, takes a set of extra stride
     arguments, one for every vector argument.  The stride arguments determine
     which elements in the array are actually processed.  For instance, if the
     stride for a particular array is set to 3, every third element in the
     array will be processed by the routine.  The stride arguments need not be
     identical.  If all stride arguments are set to 1, this call behaves
     exactly like the version without the _i in its name.

     The calculation performed is as follows:  Initialize the counter vari-
     ables J, K, L, and M to the low indices of the arrays start_vec,
     mult_vec, mult_vec_2, and result_vec.  In Fortran, the low index will be
     1;  in C, it will be 0; in Pascal, it varies depending on the declara-
     tion.
     Execute the following equations length times:
     result_vec(M) = (start_vec(J) x mult_vec(K)) x mult_vec_2(L)
     J = J + start_inc
     K = K + mult_inc
     L = L + mult_inc_2
     M = M + result_inc


     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 multiplier vector.

     start_inc
          The stride for start_vec.

     mult_vec
          A multiplier vector.

     mult_inc
          The stride for mult_vec.

     mult_vec_2
          A multiplier vector.

     mult_inc_2
          The stride for mult_vec_2.

     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 start_vec, mult_vec, and
          mult_vec_2.

     result_inc
          The stride for result_vec.

NOTES
     When vec_$mult_mult_vector_i is used to operate on matrixes in C and Pas-
     cal, start_vec, mult_vec, mult_vec_2, 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.


SEE ALSO
     vec_$add_mult_vector, vec_$sub_mult_vector, vec_$mult_add_vector,
     vec_$mult_sub_vector, vec_$mult_rsub_vector, vec_$add_add_vector,
     vec_$sub_add_vector, vec_$mult_mult_vector, vec_$dmult_mult_vector,
     vec_$dmult_mult_vector_i, vec_$imult_mult_vector,
     vec_$imult_mult_vector_i, vec_$imult_mult_vector16,
     vec_$imult_mult_vector16_i.