zunbdb5 (3)

Functions/Subroutines

subroutine zunbdb5 (M1, M2, N, X1, INCX1, X2, INCX2, Q1, LDQ1, Q2, LDQ2, WORK, LWORK, INFO)

ZUNBDB5

subroutine zunbdb5 (integerM1, integerM2, integerN, complex*16, dimension(*)X1, integerINCX1, complex*16, dimension(*)X2, integerINCX2, complex*16, dimension(ldq1,*)Q1, integerLDQ1, complex*16, dimension(ldq2,*)Q2, integerLDQ2, complex*16, dimension(*)WORK, integerLWORK, integerINFO)

ZUNBDB5

 ZUNBDB5 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 COMPLEX*16 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 COMPLEX*16 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 COMPLEX*16 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 COMPLEX*16 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 COMPLEX*16 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 zunbdb5.f.

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