# sorbdb5.f - Man Page

SRC/sorbdb5.f

## Synopsis

### Functions/Subroutines

subroutine sorbdb5 (m1, m2, n, x1, incx1, x2, incx2, q1, ldq1, q2, ldq2, work, lwork, info)
SORBDB5

## Function/Subroutine Documentation

### subroutine sorbdb5 (integer m1, integer m2, integer n, real, dimension(*) x1, integer incx1, real, dimension(*) x2, integer incx2, real, dimension(ldq1,*) q1, integer ldq1, real, dimension(ldq2,*) q2, integer ldq2, real, dimension(*) work, integer lwork, integer info)

SORBDB5

Purpose:

``` SORBDB5 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 REAL 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 REAL 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 REAL 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 REAL 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 REAL 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

NAG Ltd.

Definition at line 154 of file sorbdb5.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page sorbdb5(3) is an alias of sorbdb5.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK