


BSP parameters(3)         BSPlib level1         BSP parameters(3)



NAME
     bsp_l, bsp_g, bsp_s, bsp_nhalf -  query  the  BSP's  machine
     parameters



C SYNOPSIS
     #include "bsp_level1.h"

     double _b_s_p__s();
     double _b_s_p__l();
     double _b_s_p__g();
     int    _b_s_p__n_h_a_l_f();

FORTRAN SYNOPSIS
     DOUBLE PRECISION FUNCTION _b_s_p_s()
     DOUBLE PRECISION FUNCTION _b_s_p_l()
     DOUBLE PRECISION FUNCTION _b_s_p_g()
     INTEGER          FUNCTION _b_s_p_n_h_a_l_f()


DESCRIPTION
     These function return the BSP parameters for a machine:

     bsp_s
          is the speed of computation  of  a  process  in  flop/s
          (that  is  number  of  floating  point  operations  per
          second).


     bsp_l
          is the synchronisation latency cost in units of  bsp_s.
          i.e.,  if  _s=_1_0_0_0,  then  each processor of the machine
          could have performed 1000 floating point operations  in
          the  same  time  as all processors take to barrier syn-
          chronise.


     bsp_g
          is the asymptotic number of flops/word required for all
          processors to simultaneously communicate a message.


     bsp_nhalf
          is the number of words required to be communicated such
          that the communication performance deteriorates to _2_g

     In the current implementation of the library, the values for
     each  of  these parameters is read from a database file, and
     not calculated by experimentation at runtime.





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






BSP parameters(3)         BSPlib level1         BSP parameters(3)



FILES
     The  file  _P_R_E_F_I_X/include/bsp_parameters.ascii  contains   a
     table  of  the BSP parameters read by these functions; where
     _P_R_E_F_I_X is  the  installation  prefix  set  when  configuring
     BSPlib.


SEE ALSO
     bspparam(1), bsplib_level1(3)


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
     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



