dqrt11.f - Man Page

TESTING/LIN/dqrt11.f

Synopsis

Functions/Subroutines

double precision function dqrt11 (m, k, a, lda, tau, work, lwork)
DQRT11

Function/Subroutine Documentation

double precision function dqrt11 (integer m, integer k, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( * ) tau, double precision, dimension( lwork ) work, integer lwork)

DQRT11

Purpose:

 DQRT11 computes the test ratio

       || Q'*Q - I || / (eps * m)

 where the orthogonal matrix Q is represented as a product of
 elementary transformations.  Each transformation has the form

    H(k) = I - tau(k) v(k) v(k)'

 where tau(k) is stored in TAU(k) and v(k) is an m-vector of the form
 [ 0 ... 0 1 x(k) ]', where x(k) is a vector of length m-k stored
 in A(k+1:m,k).
Parameters

M

          M is INTEGER
          The number of rows of the matrix A.

K

          K is INTEGER
          The number of columns of A whose subdiagonal entries
          contain information about orthogonal transformations.

A

          A is DOUBLE PRECISION array, dimension (LDA,K)
          The (possibly partial) output of a QR reduction routine.

LDA

          LDA is INTEGER
          The leading dimension of the array A.

TAU

          TAU is DOUBLE PRECISION array, dimension (K)
          The scaling factors tau for the elementary transformations as
          computed by the QR factorization routine.

WORK

          WORK is DOUBLE PRECISION array, dimension (LWORK)

LWORK

          LWORK is INTEGER
          The length of the array WORK.  LWORK >= M*M + M.
Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 97 of file dqrt11.f.

Author

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Referenced By

The man page dqrt11(3) is an alias of dqrt11.f(3).

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK