SRC/cunbdb6.f(3) | Library Functions Manual | SRC/cunbdb6.f(3) |
NAME
SRC/cunbdb6.f
SYNOPSIS
Functions/Subroutines
subroutine cunbdb6 (m1, m2, n, x1, incx1, x2, incx2, q1,
ldq1, q2, ldq2, work, lwork, info)
CUNBDB6
Function/Subroutine Documentation
subroutine cunbdb6 (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)
CUNBDB6
Purpose:
CUNBDB6 orthogonalizes the column vector X = [ X1 ] [ X2 ] with respect to the columns of Q = [ Q1 ] . [ Q2 ] The columns of Q must be orthonormal. The orthogonalized vector will be zero if and only if it lies entirely in the range of Q. The projection is computed with at most two iterations of the classical Gram-Schmidt algorithm, see * L. Giraud, J. Langou, M. Rozložník. 'On the round-off error analysis of the Gram-Schmidt algorithm with reorthogonalization.' 2002. CERFACS Technical Report No. TR/PA/02/33. URL: https://www.cerfacs.fr/algor/reports/2002/TR_PA_02_33.pdf
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.
Definition at line 157 of file cunbdb6.f.
Author
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