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house_qr
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1994-10-22
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521b
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27 lines
// house_qr.r
// Given A, with M >= N, the following function finds Householder
// matrices H1,...Hn, such that if Q = H1*...Hn, then Q'*A = R is
// upper triangular.
// House.qr returns a MxN matrix, with the upper triangular part
// containing [R]
house_qr = function ( A )
{
local (A)
m = A.nr; n = A.nc;
v = zeros(m,1);
for(j in 1:n)
{
v[j:m] = house_v( A[j:m;j] );
A[j:m;j:n] = house_row( A[j:m;j:n], v[j:m] );
if (j < m)
{
A[ (j+1):m;j ] = v[(j+1):m];
}
}
return A;
};