


bsp_set_tagsize(3)      BSPlib FUNCTIONS       bsp_set_tagsize(3)



NAME
     bsp_set_tagsize - tag size of a BSMP packet.


C SYNOPSIS
     #include "bsp.h"

     void bsp_set_tagsize(int *_t_a_g__b_y_t_e_s);

FORTRAN SYNOPSIS
     SUBROUTINE  bspsettagsize(tag_bytes)
       INTEGER, intent(INOUT) :: _t_a_g__b_y_t_e_s


DESCRIPTION
     Allowing the user to set the tag size  enables  the  use  of
     tags that are appropriate for the communication requirements
     of each superstep.  This should be  particularly  useful  in
     the development of subroutines either in user programs or in
     libraries.

     The procedure must be called collectively by all  processes.
     A  change  in  tag size takes effect in the following super-
     step; it then becomes _v_a_l_i_d.

     The value of _t_a_g__b_y_t_e_s on entry to the procedure,  specifies
     the size of the fixed-length portion of every message in the
     current and succeeding supersteps; the default tag  size  is
     zero.  On return from the procedure, _t_a_g__b_y_t_e_s is changed to
     reflect the previous value of the tag size.


SEE ALSO
     bsmp(3)    ,bsp_send(3),    bsp_get_tag(3),    bsp_qsize(3),
     bsp_move(3), bsp_hpmove(3)

     ``_B_S_P_l_i_b: _T_h_e _B_S_P _P_r_o_g_r_a_m_m_i_n_g _L_i_b_r_a_r_y'' Jonathan M. D. Hill,
     Bill  McColl,  Dan  C.  Stefanescu,  Mark W. Goudreau, Kevin
     Lang, Satish B. Rao, , Torsten Suel, Thanasis Tsantilas, and
     Rob  Bisseling.  Parallel  Computing,  to  appear  1998. See
     _h_t_t_p://_w_w_w._b_s_p-_w_o_r_l_d_w_i_d_e._o_r_g for more details.


NOTES
     i    The tag size of outgoing messages is prescribed by  the
          tag size that is valid in the current superstep.


     ii   The tag  size  of  messages  in  the  system  queue  is
          prescribed by the tag size that was valid in the previ-
          ous superstep.




Oxford BSP Toolset  Last change: 1.4 25/9/98                    1






bsp_set_tagsize(3)      BSPlib FUNCTIONS       bsp_set_tagsize(3)



     iii  bsp_set_tagsize(3) must be called by _a_l_l processes with
          the  same  argument  in  the  same  superstep.  In this
          respect, it is similar to bsp_push_reg(3).


     iv   bsp_set_tagsize(3) takes effect in the next superstep.



     v    Given a sequence of bsp_set_tagsize(3) within the  same
          superstep,  then the value of the last of these will be
          used as the tag size for the next superstep.


     vi   The default tag size is 0.


BUGS
     Problems  and  bug  reports  should  be  mailed  to  _b_s_p_l_i_b-
     _b_u_g_s@_c_o_m_l_a_b._o_x._a_c._u_k


AUTHORS
     The Oxford BSP Toolset implementation of BSPlib was  written
     by Jonathan.Hill@comlab.ox.ac.uk
     http://www.comlab.ox.ac.uk/oucl/people/jonathan.hill.html





























Oxford BSP Toolset  Last change: 1.4 25/9/98                    2



