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function Y = spqr_qmult (H,X,method) %#ok
%SPQR_QMULT computes Q'*X, Q*X, X*Q', or X*Q with Q in Householder form.
% Usage: Y = spqr_qmult (Q,X,method)
%
% method = 0: Y = Q'*X default if 3rd input argument is not present.
% method = 1: Y = Q*X
% method = 2: Y = X*Q'
% method = 3: Y = X*Q
%
% Example:
% These two examples both compute the min-norm solution to an
% under determined system, but the latter is much more efficient:
%
% [Q,R,E] = spqr(A') ; x = Q*(R'\(E'*b)) ;
%
% [Q,R,E] = spqr(A',struct('Q','Householder')) ;
% x = spqr_qmult(Q,R'\(E'*b),1) ;
%
% See also SPQR, SPQR_SOLVE, QR, MTIMES
% Copyright 2008, Timothy A. Davis, http://www.suitesparse.com
help spqr_qmult
error ('spqr_qmult mexFunction not found') ;
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