39964380f1
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@357 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
51 lines
1.2 KiB
Prolog
51 lines
1.2 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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%%
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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, Num) :-
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!,
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Half is Num // 2,
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format( 'Proc 0: Calculating ~q..~q~n', [1, Half] ),
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calc( 1, Half, 0, R1 ),
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format( 'Proc 0: Done! (~q)~n', [R1] ),
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mpi_receive( R2, Source, Tag ), % Receive any Source, any Tag
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format( 'Proc ~q said: ~q (Tag: ~q)~n', [Source,R2,Tag] ),
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% mpi_receive( R2, 1, 1 ), % Be more particular
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Res is R1 + R2,
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format( 'Sum(1..~q) = ~q~n', [Num,Res] ).
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do(1, Num) :-
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!,
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Half is Num // 2,
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format( 'Proc 1: Calculating ~q..~q~n', [Half,Num] ),
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calc( Half, Num, 0, Res ),
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format( 'Proc 1: Done! (~q)~n', [Res] ),
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mpi_send( Res, 0, 1 ).
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%%
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%% This is the entry point
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%%
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start(Num) :-
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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, Num ),
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format( 'Rank ~q finished!~n', [Rank] ).
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