table of contents
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/sort01.f(3) | Library Functions Manual | /home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/sort01.f(3) |
NAME¶
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/sort01.f
SYNOPSIS¶
Functions/Subroutines¶
subroutine SORT01 (rowcol, m, n, u, ldu, work, lwork,
resid)
SORT01
Function/Subroutine Documentation¶
subroutine SORT01 (character rowcol, integer m, integer n, real, dimension( ldu, * ) u, integer ldu, real, dimension( * ) work, integer lwork, real resid)¶
SORT01
Purpose:
!> !> SORT01 checks that the matrix U is orthogonal 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'. !>
Parameters
ROWCOL
!> 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 !>
M
!> M is INTEGER !> The number of rows of the matrix U. !>
N
!> N is INTEGER !> The number of columns of the matrix U. !>
U
!> U is REAL array, dimension (LDU,N) !> The orthogonal 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'. !>
LDU
!> LDU is INTEGER !> The leading dimension of the array U. LDU >= max(1,M). !>
WORK
!> WORK is REAL array, dimension (LWORK) !>
LWORK
!> LWORK is INTEGER !> The length of the array WORK. For best performance, LWORK !> should be at least N*(N+1) if ROWCOL = 'C' or M*(M+1) if !> ROWCOL = 'R', but the test will be done even if LWORK is 0. !>
RESID
!> RESID is REAL !> RESID = norm( I - U * U' ) / ( n * EPS ), if ROWCOL = 'R', or !> RESID = norm( I - U' * U ) / ( m * EPS ), if ROWCOL = 'C'. !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 115 of file sort01.f.
Author¶
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