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dorbdb5.f(3) LAPACK dorbdb5.f(3)

NAME

dorbdb5.f -

SYNOPSIS

Functions/Subroutines


subroutine dorbdb5 (M1, M2, N, X1, INCX1, X2, INCX2, Q1, LDQ1, Q2, LDQ2, WORK, LWORK, INFO)
 
DORBDB5

Function/Subroutine Documentation

subroutine dorbdb5 (integerM1, integerM2, integerN, double precision, dimension(*)X1, integerINCX1, double precision, dimension(*)X2, integerINCX2, double precision, dimension(ldq1,*)Q1, integerLDQ1, double precision, dimension(ldq2,*)Q2, integerLDQ2, double precision, dimension(*)WORK, integerLWORK, integerINFO)

DORBDB5

Purpose: 

 DORBDB5 orthogonalizes the column vector
      X = [ X1 ]
          [ X2 ]
 with respect to the columns of
      Q = [ Q1 ] .
          [ Q2 ]
 The columns of Q must be orthonormal.


 If the projection is zero according to Kahan's "twice is enough"
 criterion, then some other vector from the orthogonal complement
 is returned. This vector is chosen in an arbitrary but deterministic
 way..fi

 

Parameters:

M1 

          M1 is INTEGER
           The dimension of X1 and the number of rows in Q1. 0 <= M1.
M2 
          M2 is INTEGER
           The dimension of X2 and the number of rows in Q2. 0 <= M2.
N 
          N is INTEGER
           The number of columns in Q1 and Q2. 0 <= N.
X1 
          X1 is DOUBLE PRECISION array, dimension (M1)
           On entry, the top part of the vector to be orthogonalized.
           On exit, the top part of the projected vector.
INCX1 
          INCX1 is INTEGER
           Increment for entries of X1.
X2 
          X2 is DOUBLE PRECISION array, dimension (M2)
           On entry, the bottom part of the vector to be
           orthogonalized. On exit, the bottom part of the projected
           vector.
INCX2 
          INCX2 is INTEGER
           Increment for entries of X2.
Q1 
          Q1 is DOUBLE PRECISION array, dimension (LDQ1, N)
           The top part of the orthonormal basis matrix.
LDQ1 
          LDQ1 is INTEGER
           The leading dimension of Q1. LDQ1 >= M1.
Q2 
          Q2 is DOUBLE PRECISION array, dimension (LDQ2, N)
           The bottom part of the orthonormal basis matrix.
LDQ2 
          LDQ2 is INTEGER
           The leading dimension of Q2. LDQ2 >= M2.
WORK 
          WORK is DOUBLE PRECISION array, dimension (LWORK)
LWORK 
          LWORK is INTEGER
           The dimension of the array WORK. LWORK >= N.
INFO 
          INFO is INTEGER
           = 0:  successful exit.
           < 0:  if INFO = -i, the i-th argument had an illegal value.
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
July 2012
Definition at line 156 of file dorbdb5.f.

Author

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