sqrt11.f - Man Page

real function sqrt11 (m, k, a, lda, tau, work, lwork)
SQRT11

SQRT11

Purpose:

 SQRT11 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 REAL 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 REAL array, dimension (K)
          The scaling factors tau for the elementary transformations as
          computed by the QR factorization routine.

WORK

          WORK is REAL 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 sqrt11.f.