# dbdt02.f - Man Page

TESTING/EIG/dbdt02.f

## Synopsis

### Functions/Subroutines

subroutine dbdt02 (m, n, b, ldb, c, ldc, u, ldu, work, resid)
DBDT02

## Function/Subroutine Documentation

### subroutine dbdt02 (integer m, integer n, double precision, dimension( ldb, * ) b, integer ldb, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension( ldu, * ) u, integer ldu, double precision, dimension( * ) work, double precision resid)

DBDT02

Purpose:

``` DBDT02 tests the change of basis C = U**H * B by computing the
residual

RESID = norm(B - U * C) / ( max(m,n) * norm(B) * EPS ),

where B and C are M by N matrices, U is an M by M orthogonal matrix,
and EPS is the machine precision.```
Parameters

M

```          M is INTEGER
The number of rows of the matrices B and C and the order of
the matrix Q.```

N

```          N is INTEGER
The number of columns of the matrices B and C.```

B

```          B is DOUBLE PRECISION array, dimension (LDB,N)
The m by n matrix B.```

LDB

```          LDB is INTEGER
The leading dimension of the array B.  LDB >= max(1,M).```

C

```          C is DOUBLE PRECISION array, dimension (LDC,N)
The m by n matrix C, assumed to contain U**H * B.```

LDC

```          LDC is INTEGER
The leading dimension of the array C.  LDC >= max(1,M).```

U

```          U is DOUBLE PRECISION array, dimension (LDU,M)
The m by m orthogonal matrix U.```

LDU

```          LDU is INTEGER
The leading dimension of the array U.  LDU >= max(1,M).```

WORK

`          WORK is DOUBLE PRECISION array, dimension (M)`

RESID

```          RESID is DOUBLE PRECISION
RESID = norm(B - U * C) / ( max(m,n) * norm(B) * EPS ),```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 111 of file dbdt02.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page dbdt02(3) is an alias of dbdt02.f(3).

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