Description of geqrf

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Category:mtl2lapack

Component type:function

Prototype

template <class LapackMatA,class VectorT> int geqrf(LapackMatA& a, VectorT & tau) ;

Description

QR Factorization of a MxN General Matrix A.

a (IN/OUT - matrix(M,N)) On entry, the coefficient matrix A. On exit , the upper triangle and diagonal 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.
tau (OUT - vector (min(M,N))) Vector of the 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