145 lines
3.3 KiB
Prolog
145 lines
3.3 KiB
Prolog
%% demo1_mpe.pl
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%%
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%% This file was originally created on 3/7/2003
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%% by Stasinos Konstantopoulos <konstant@let.rug.nl>
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%% as part of the YAP Prolog distribution.
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%%
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%% This file is in the Public Domain.
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:- use_module(library(mpi)).
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:- use_module(library(mpe)).
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%% demo1_mpe.pl is the same as demo1.pl, except
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%% that MPE is used to log MPI activity.
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% make the `floor' operator return integer values
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:- set_prolog_flag(language, iso).
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%%
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%% This the calculation that needs to be performed, in this case
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%% the sum of [From..To]
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%%
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calc(From, From, Acc, Res) :- !,
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Res is Acc + From.
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calc(From, To, Acc, Res) :- !,
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Acc1 is Acc + To,
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To1 is To - 1,
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calc(From, To1, Acc1, Res).
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%%
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%% The master node sends teh task definition to
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%% the workers and then collects the results
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%%
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do(0, NumProc):-
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!,
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% processing state
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mpe_create_event(Ev1),
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mpe_create_event(Ev2),
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mpe_create_state(Ev1,Ev2,processing,green),
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% bcasting state
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mpe_create_event(Ev3),
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mpe_create_event(Ev4),
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mpe_create_state(Ev3,Ev4,bcasting,red),
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% sending/recving state
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mpe_create_event(Ev5),
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mpe_create_event(Ev6),
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mpe_create_state(Ev5,Ev6,'sending/receiving',brown),
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% pretend that the other nodes do not have
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% access to the task definition.
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% retrieve it and broadcast it.
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get_value(from, From),
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get_value(to, To),
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mpe_log(Ev3,0,event3),
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mpi_bcast(msg(From,To), 0),
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mpe_log(Ev4,0,event4),
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% loop to collect and accumulate partial results
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% from the workers
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set_value(n, NumProc),
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set_value(acc, 0),
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repeat,
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mpe_log(Ev5,0,event5),
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mpi_receive(T, Source, Tag),
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mpe_log(Ev6,0,event6),
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format( '0: Proc ~q said: ~q (Tag: ~q)~n', [Source,T,Tag] ),
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% accumulate results
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get_value(acc, Acc),
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NewAcc is Acc + T,
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set_value(acc, NewAcc),
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% processors still left
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get_value(n, Counter),
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NewCounter is Counter - 1,
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set_value(n, NewCounter),
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NewCounter == 1,
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!,
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format('0: Sum(~q..~q) = ~q.~n', [From,To,NewAcc]).
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%%
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%% The workers hear from the master what needs to
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%% be done, do the work and then send the results back.
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%%
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do(Rank, NumProc):-
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!,
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% processing state
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mpe_create_event(Ev1),
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mpe_create_event(Ev2),
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mpe_create_state(Ev1,Ev2,processing,green),
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% bcasting state
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mpe_create_event(Ev3),
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mpe_create_event(Ev4),
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mpe_create_state(Ev3,Ev4,bcasting,red),
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% sending/recving state
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mpe_create_event(Ev5),
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mpe_create_event(Ev6),
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mpe_create_state(Ev5,Ev6,'sending/receiving',brown),
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% catch the task broadcast
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mpe_log(Ev3,0,event3),
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mpi_bcast(Msg, 0),
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mpe_log(Ev4,0,event4),
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Msg = msg(From,To),
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format( '~q: All are calculating ~q..~q.~n', [Rank,From,To] ),
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MyFrom is floor(To * (Rank - 1) / (NumProc - 1)) + From,
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MyTo is floor(To * Rank / (NumProc - 1)) + From - 1,
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format( '~q: I am calculating ~q..~q.~n', [Rank,MyFrom,MyTo] ),
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% do the job
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mpe_log(Ev1,0,event1),
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calc( MyFrom, MyTo, 0, Result ),
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mpe_log(Ev2,0,event2),
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format( '~q: sending ~q to 0. (Tag: 1)~n', [Rank,Result] ),
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% send back the results
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mpe_log(Ev5,0,event5),
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mpi_send(Result, 0, 1),
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mpe_log(Ev6,0,event6).
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%%
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%% This is the entry point
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%%
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start(From, To):-
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% store the task definition
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set_value(from, From),
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set_value(to, To),
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mpi_open(Rank, NumProc, ProcName),
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format('Rank: ~q NumProc: ~q, ProcName: ~q~n', [Rank,NumProc,ProcName]),
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mpe_open,
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do(Rank, NumProc),
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format( 'Rank ~q finished!~n', [Rank] ),
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mpe_close( demo1_mpe ),
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mpi_close.
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