# cunt03.f - Man Page

TESTING/EIG/cunt03.f

## Synopsis

### Functions/Subroutines

subroutine cunt03 (rc, mu, mv, n, k, u, ldu, v, ldv, work, lwork, rwork, result, info)
CUNT03

## Function/Subroutine Documentation

### subroutine cunt03 (character*( * ) rc, integer mu, integer mv, integer n, integer k, complex, dimension( ldu, * ) u, integer ldu, complex, dimension( ldv, * ) v, integer ldv, complex, dimension( * ) work, integer lwork, real, dimension( * ) rwork, real result, integer info)

CUNT03

Purpose:

CUNT03 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 CUNT03 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 CUNT03 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
CUNT03 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 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 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 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 REAL array, dimension (max(MV,N))

RESULT

RESULT is REAL
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 cunt03.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page cunt03(3) is an alias of cunt03.f(3).

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