2334010f7f
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@840 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
71 lines
1.6 KiB
Prolog
71 lines
1.6 KiB
Prolog
%% demo1.pl -- Stasinos Konstantopoulos
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%% konstant@let.rug.nl, Thu Jan 24 2002
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%%
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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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%% This spreads the work among the processors
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%% and collects the results.
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%%
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do(0, NumProc):-
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!,
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% broadcast task
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mpi_bcast(10, 0),
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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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mpi_receive(T, Source, Tag),
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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: Result: ~q.~n', [
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do(Rank, NumProc):-
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!,
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% catch the task broadcast
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mpi_bcast(Job, 0),
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From is floor(Job * (Rank - 1) / (NumProc - 1)),
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To is floor(Job * Rank / (NumProc - 1)) - 1,
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format( '~q: I am calculating ~q..~q.~n', [Rank,From,To] ),
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% do the job
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calc( From, To, 0, Result ),
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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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mpi_send(Result, 0, 1).
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%%
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%% This is the entry point
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%%
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start:-
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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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do(Rank, NumProc),
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format( 'Rank ~q finished!~n', [Rank] ),
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mpi_close.
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