dpbtf2 man page on Scientific

 Man page or keyword search:   man All Sections 1 - General Commands 2 - System Calls 3 - Subroutines, Functions 4 - Special Files 5 - File Formats 6 - Games and Screensavers 7 - Macros and Conventions 8 - Maintenence Commands 9 - Kernel Interface New Commands Server 4.4BSD AIX Alpinelinux Archlinux Aros BSDOS BSDi Bifrost CentOS Cygwin Darwin Debian DigitalUNIX DragonFly ElementaryOS Fedora FreeBSD Gentoo GhostBSD HP-UX Haiku Hurd IRIX Inferno JazzOS Kali Knoppix LinuxMint MacOSX Mageia Mandriva Manjaro Minix MirBSD NeXTSTEP NetBSD OPENSTEP OSF1 OpenBSD OpenDarwin OpenIndiana OpenMandriva OpenServer OpenSuSE OpenVMS Oracle PC-BSD Peanut Pidora Plan9 QNX Raspbian RedHat Scientific Slackware SmartOS Solaris SuSE SunOS Syllable Tru64 UNIXv7 Ubuntu Ultrix UnixWare Xenix YellowDog aLinux   26626 pages apropos Keyword Search (all sections) Output format html ascii pdf view pdf save postscript
[printable version]

DPBTF2(1)		 LAPACK routine (version 3.2)		     DPBTF2(1)

NAME
DPBTF2  - computes the Cholesky factorization of a real symmetric posi‐
tive definite band matrix A

SYNOPSIS
SUBROUTINE DPBTF2( UPLO, N, KD, AB, LDAB, INFO )

CHARACTER	  UPLO

INTEGER	  INFO, KD, LDAB, N

DOUBLE	  PRECISION AB( LDAB, * )

PURPOSE
DPBTF2 computes the Cholesky factorization of a real symmetric positive
definite band matrix A.	The factorization has the form
A = U' * U ,	if UPLO = 'U', or
A = L	 * L',	if UPLO = 'L',
where  U is an upper triangular matrix, U' is the transpose of U, and L
is lower triangular.
This is the unblocked version of the algorithm, calling Level 2 BLAS.

ARGUMENTS
UPLO    (input) CHARACTER*1
Specifies whether the upper or lower  triangular	 part  of  the
symmetric matrix A is stored:
= 'U':  Upper triangular
= 'L':  Lower triangular

N       (input) INTEGER
The order of the matrix A.  N >= 0.

KD      (input) INTEGER
The number of super-diagonals of the matrix A if UPLO = 'U', or
the number of sub-diagonals if UPLO = 'L'.  KD >= 0.

AB      (input/output) DOUBLE PRECISION array, dimension (LDAB,N)
On entry, the upper or lower triangle  of  the  symmetric  band
matrix A, stored in the first KD+1 rows of the array.  The j-th
column of A is stored in the j-th column of  the	 array	AB  as
follows:	 if  UPLO  = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-
kd)<=i<=j;  if  UPLO  =	'L',  AB(1+i-j,j)     =	  A(i,j)   for
j<=i<=min(n,j+kd).  On exit, if INFO = 0, the triangular factor
U or L from the Cholesky factorization A = U'*U or A = L*L'  of
the band matrix A, in the same storage format as A.

LDAB    (input) INTEGER
The leading dimension of the array AB.  LDAB >= KD+1.

INFO    (output) INTEGER
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value
>  0: if INFO = k, the leading minor of order k is not positive
definite, and the factorization could not be completed.

FURTHER DETAILS
The band storage scheme is illustrated by the following example, when N
= 6, KD = 2, and UPLO = 'U':
On entry:		       On exit:
*	*   a13	 a24  a35  a46	    *	 *   u13  u24  u35  u46
*   a12  a23	 a34  a45  a56	    *	u12  u23  u34  u45  u56
a11	a22  a33  a44  a55  a66	    u11	 u22  u33  u44	u55  u66 Simi‐
larly, if UPLO = 'L' the format of A is as follows:
On entry:		       On exit:
a11  a22  a33	 a44  a55  a66	   l11	l22  l33  l44  l55  l66
a21  a32  a43	 a54  a65   *	   l21	l32  l43  l54  l65   *
a31  a42  a53	 a64   *    *	   l31	l42  l53  l64	*     *	 Array
elements marked * are not used by the routine.

LAPACK routine (version 3.2)	 November 2008			     DPBTF2(1)
[top]

List of man pages available for Scientific

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.