This repository has been archived on 2023-08-20. You can view files and clone it, but cannot push or open issues or pull requests.
yap-6.3/CLPQR/clpqr/examples/monash/invert
vsc e5f4633c39 This commit was generated by cvs2svn to compensate for changes in r4,
which included commits to RCS files with non-trunk default branches.


git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@5 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
2001-04-09 19:54:03 +00:00

94 lines
1.8 KiB
Plaintext

/*
**********************************************************************
*
* CLP(R) Version 2.0 (Example Programs Release)
* (C) Copyright, March 1986, Monash University
*
**********************************************************************
*/
%
% Matrix inversion package. The goal ?- go
% invers a matrix, prints the inverse, then multiplies the two,
% getting the identity matrix, and prints that.
%
sizemat(M,R,C):-
mylength(M,R),
allvec(M,C).
allvec([],C).
allvec([H|T],C):-
mylength(H,C),
allvec(T,C).
mylength([],0). % length->mylength by ch
mylength([H],1). % to avoid name clash
mylength([H|T],L+1):-
mylength(T,L).
matmul([H|T],B,[H1|T1]):-
rowmul(H,B,H1),
matmul(T,B,T1).
matmul([],_,[]).
rowmul(AV,[H|T],[H1|T1]):-
vecmul(AV,H,0,H1),
rowmul(AV,T,T1).
rowmul(_,[],[]).
vecmul([H1|T1],[H2|T2],IN,OUT):-
TMP = IN + H1 * H2,
vecmul(T1,T2,TMP,OUT).
vecmul([],[],S,S).
rowtocol(A,[H|T]):-
stripfirst(A,H,REST),
rowtocol(REST,T).
rowtocol(A,[]).
stripfirst([H|T],[H1|T1],[H2|T2]):-
stripvec(H,H1,H2),
stripfirst(T,T1,T2).
stripfirst([],[],[]).
stripvec([H|T],H,T).
putmat([H|T]):-
putvec(H),
putmat(T).
putmat([]).
putvec([H|T]):-
printf(" %9.4f ",[H]),
putvec(T).
putvec([]):-
nl.
go:- M = [ [4,5,6], [1,5,3], [1,8,9] ],
I = [ [1,0,0], [0,1,0], [0,0,1] ],
sizemat(N,3,3),
sizemat(NR,3,3),
sizemat(T,3,3),
matmul(M,N,I),
rowtocol(NR,N),
matmul(M,N,T),
printf(" NR = \n",[]),
putmat(NR),
printf(" T = \n",[]),
putmat(T).
% Output:
% NR =
% 0.2917 0.0417 -0.2083
% -0.0833 0.4167 -0.0833
% 0.0417 -0.3750 0.2083
% T =
% 1.0000 0.0000 0.0000
% 0.0000 1.0000 0.0000
% 0.0000 0.0000 1.0000
?- printf("\n>>> Sample goal: go/0\n", []).