# zunt03.f - Man Page

TESTING/EIG/zunt03.f

## Synopsis

### Functions/Subroutines

subroutine zunt03 (rc, mu, mv, n, k, u, ldu, v, ldv, work, lwork, rwork, result, info)
ZUNT03

## Function/Subroutine Documentation

### subroutine zunt03 (character*( * ) rc, integer mu, integer mv, integer n, integer k, complex*16, dimension( ldu, * ) u, integer ldu, complex*16, dimension( ldv, * ) v, integer ldv, complex*16, dimension( * ) work, integer lwork, double precision, dimension( * ) rwork, double precision result, integer info)

ZUNT03

Purpose:

``` ZUNT03 compares two unitary matrices U and V to see if their
corresponding rows or columns span the same spaces.  The rows are
checked if RC = 'R', and the columns are checked if RC = 'C'.

RESULT is the maximum of

| V*V' - I | / ( MV ulp ), if RC = 'R', or

| V'*V - I | / ( MV ulp ), if RC = 'C',

and the maximum over rows (or columns) 1 to K of

| U(i) - S*V(i) |/ ( N ulp )

where abs(S) = 1 (chosen to minimize the expression), U(i) is the
i-th row (column) of U, and V(i) is the i-th row (column) of V.```
Parameters

RC

```          RC is CHARACTER*1
If RC = 'R' the rows of U and V are to be compared.
If RC = 'C' the columns of U and V are to be compared.```

MU

```          MU is INTEGER
The number of rows of U if RC = 'R', and the number of
columns if RC = 'C'.  If MU = 0 ZUNT03 does nothing.
MU must be at least zero.```

MV

```          MV is INTEGER
The number of rows of V if RC = 'R', and the number of
columns if RC = 'C'.  If MV = 0 ZUNT03 does nothing.
MV must be at least zero.```

N

```          N is INTEGER
If RC = 'R', the number of columns in the matrices U and V,
and if RC = 'C', the number of rows in U and V.  If N = 0
ZUNT03 does nothing.  N must be at least zero.```

K

```          K is INTEGER
The number of rows or columns of U and V to compare.
0 <= K <= max(MU,MV).```

U

```          U is COMPLEX*16 array, dimension (LDU,N)
The first matrix to compare.  If RC = 'R', U is MU by N, and
if RC = 'C', U is N by MU.```

LDU

```          LDU is INTEGER
The leading dimension of U.  If RC = 'R', LDU >= max(1,MU),
and if RC = 'C', LDU >= max(1,N).```

V

```          V is COMPLEX*16 array, dimension (LDV,N)
The second matrix to compare.  If RC = 'R', V is MV by N, and
if RC = 'C', V is N by MV.```

LDV

```          LDV is INTEGER
The leading dimension of V.  If RC = 'R', LDV >= max(1,MV),
and if RC = 'C', LDV >= max(1,N).```

WORK

`          WORK is COMPLEX*16 array, dimension (LWORK)`

LWORK

```          LWORK is INTEGER
The length of the array WORK.  For best performance, LWORK
should be at least N*N if RC = 'C' or M*M if RC = 'R', but
the tests will be done even if LWORK is 0.```

RWORK

`          RWORK is DOUBLE PRECISION array, dimension (max(MV,N))`

RESULT

```          RESULT is DOUBLE PRECISION
The value computed by the test described above.  RESULT is
limited to 1/ulp to avoid overflow.```

INFO

```          INFO is INTEGER
0  indicates a successful exit
-k indicates the k-th parameter had an illegal value```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 160 of file zunt03.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page zunt03(3) is an alias of zunt03.f(3).

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