zqrt11.f - Man Page

double precision function zqrt11 (m, k, a, lda, tau, work, lwork)
ZQRT11

ZQRT11

Purpose:

 ZQRT11 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 COMPLEX*16 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 COMPLEX*16 array, dimension (K)
          The scaling factors tau for the elementary transformations as
          computed by the QR factorization routine.

WORK

          WORK is COMPLEX*16 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 zqrt11.f.