Description of geqpf

geqpf		Programmers Guide
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Category:mtl2lapack

Component type:function

Prototype

template <class LapackMatA, class VectorInt, class VectorT> int geqpf(LapackMatA & a, VectorInt & jpivot, VectorT & tau) ;

Description

QR Factorization with Column Pivoting of a MxN General Matrix A.

a (IN/OUT - matrix(M,N)) On entry, the coefficient matrix A. On exit, its upper triangle is the min(M,N)-by-N upper triangular matrix R. The lower triangle, together with the tau vector, is the orthogonal matrix Q as a product of min(M,N) elementary reflectors.
jpivot (IN/OUT - vector(N)) Integer vector. On entry, if JPVT(i) != 0, the i-th column of A is permuted to the front of A*P. If JPVT(i) = 0, the i-th column of A is a free column. On exit, if jpivot(i) = k, then the i-th column of A*P was the k-th column of A.
tau (OUT - vector (min(M,N))) Vector of same numerical type as A. The scalar factors of the elementary reflectors.
info (OUT - int) 0 : function completed normally < 0 : The ith argument, where i = abs(return value) had an illegal value.

Definition

mtl2lapack.h

Preconditions

Complexity

Example

Notes

See also