.TH "TESTING/EIG/zunt01.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*-
.ad l
.nh
.SH NAME
TESTING/EIG/zunt01.f
.SH SYNOPSIS
.br
.PP
.SS "Functions/Subroutines"

.in +1c
.ti -1c
.RI "subroutine \fBzunt01\fP (rowcol, m, n, u, ldu, work, lwork, rwork, resid)"
.br
.RI "\fBZUNT01\fP "
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "subroutine zunt01 (character rowcol, integer m, integer n, complex*16, dimension( ldu, * ) u, integer ldu, complex*16, dimension( * ) work, integer lwork, double precision, dimension( * ) rwork, double precision resid)"

.PP
\fBZUNT01\fP 
.PP
\fBPurpose:\fP
.RS 4

.PP
.nf
 ZUNT01 checks that the matrix U is unitary by computing the ratio

    RESID = norm( I - U*U' ) / ( n * EPS ), if ROWCOL = 'R',
 or
    RESID = norm( I - U'*U ) / ( m * EPS ), if ROWCOL = 'C'\&.

 Alternatively, if there isn't sufficient workspace to form
 I - U*U' or I - U'*U, the ratio is computed as

    RESID = abs( I - U*U' ) / ( n * EPS ), if ROWCOL = 'R',
 or
    RESID = abs( I - U'*U ) / ( m * EPS ), if ROWCOL = 'C'\&.

 where EPS is the machine precision\&.  ROWCOL is used only if m = n;
 if m > n, ROWCOL is assumed to be 'C', and if m < n, ROWCOL is
 assumed to be 'R'\&.
.fi
.PP
 
.RE
.PP
\fBParameters\fP
.RS 4
\fIROWCOL\fP 
.PP
.nf
          ROWCOL is CHARACTER
          Specifies whether the rows or columns of U should be checked
          for orthogonality\&.  Used only if M = N\&.
          = 'R':  Check for orthogonal rows of U
          = 'C':  Check for orthogonal columns of U
.fi
.PP
.br
\fIM\fP 
.PP
.nf
          M is INTEGER
          The number of rows of the matrix U\&.
.fi
.PP
.br
\fIN\fP 
.PP
.nf
          N is INTEGER
          The number of columns of the matrix U\&.
.fi
.PP
.br
\fIU\fP 
.PP
.nf
          U is COMPLEX*16 array, dimension (LDU,N)
          The unitary matrix U\&.  U is checked for orthogonal columns
          if m > n or if m = n and ROWCOL = 'C'\&.  U is checked for
          orthogonal rows if m < n or if m = n and ROWCOL = 'R'\&.
.fi
.PP
.br
\fILDU\fP 
.PP
.nf
          LDU is INTEGER
          The leading dimension of the array U\&.  LDU >= max(1,M)\&.
.fi
.PP
.br
\fIWORK\fP 
.PP
.nf
          WORK is COMPLEX*16 array, dimension (LWORK)
.fi
.PP
.br
\fILWORK\fP 
.PP
.nf
          LWORK is INTEGER
          The length of the array WORK\&.  For best performance, LWORK
          should be at least N*N if ROWCOL = 'C' or M*M if
          ROWCOL = 'R', but the test will be done even if LWORK is 0\&.
.fi
.PP
.br
\fIRWORK\fP 
.PP
.nf
          RWORK is DOUBLE PRECISION array, dimension (min(M,N))
          Used only if LWORK is large enough to use the Level 3 BLAS
          code\&.
.fi
.PP
.br
\fIRESID\fP 
.PP
.nf
          RESID is DOUBLE PRECISION
          RESID = norm( I - U * U' ) / ( n * EPS ), if ROWCOL = 'R', or
          RESID = norm( I - U' * U ) / ( m * EPS ), if ROWCOL = 'C'\&.
.fi
.PP
 
.RE
.PP
\fBAuthor\fP
.RS 4
Univ\&. of Tennessee 
.PP
Univ\&. of California Berkeley 
.PP
Univ\&. of Colorado Denver 
.PP
NAG Ltd\&. 
.RE
.PP

.PP
Definition at line \fB124\fP of file \fBzunt01\&.f\fP\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for LAPACK from the source code\&.