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cunbdb5.f(3) LAPACK cunbdb5.f(3)

NAME

cunbdb5.f

SYNOPSIS

Functions/Subroutines


subroutine cunbdb5 (M1, M2, N, X1, INCX1, X2, INCX2, Q1, LDQ1, Q2, LDQ2, WORK, LWORK, INFO)
CUNBDB5

Function/Subroutine Documentation

subroutine cunbdb5 (integer M1, integer M2, integer N, complex, dimension(*) X1, integer INCX1, complex, dimension(*) X2, integer INCX2, complex, dimension(ldq1,*) Q1, integer LDQ1, complex, dimension(ldq2,*) Q2, integer LDQ2, complex, dimension(*) WORK, integer LWORK, integer INFO)

CUNBDB5

Purpose:


CUNBDB5 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.

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 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 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 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 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 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 158 of file cunbdb5.f.

Author

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Tue Nov 14 2017 Version 3.8.0