f01qdf

f01qdf © Numerical Algorithms Group, 2002.

Purpose

T F01QDF Operations with orthogonal matrices, compute QB or Q B after factorization by F01QCF or F01QFF

Synopsis

[b,ifail] = f01qdf(a,zeta,b<,trans,wheret,ifail>)

Description

 
 Q is assumed to be given by
 
                                        T
                         Q=(Q Q   ...Q ) ,
                             n n-1    1  
 
 Q  being given in the form
  k                    
 
                                (I 0 )
                             Q =(0 T )
                              k (   k)
 
 where
 
                                    T
                            T =I-u u ,
                             k    k k
 
                              ((zeta) )
                              (      k)
                           u =(z      ),
                            k ( k     )
 
 (zeta)  is a scalar and z  is an (m-k) element vector. z  must be
       k                  k                              k      
 supplied in the kth column of A in elements A(k+1,k),...,A(m,k) 
 and (zeta)  must be supplied either in A(k,k) or in ZETA(k), 
           k                                                 
 depending upon the parameter WHERET.
 
 To obtain Q explicitly B may be set to I and pre-multiplied by Q.
                                        T
 This is more efficient than obtaining Q .

Parameters

f01qdf

Required Input Arguments:

a (:,:)                               real
zeta (:)                              real
b (:,:)                               real

Optional Input Arguments:                       <Default>

trans (1)                             string   'n'
wheret (1)                            string   's'
ifail                                 integer  -1

Output Arguments:

b (:,:)                               real
ifail                                 integer