# CentOS 7.0 - man page for sgbbrd (centos section 3)

```sgbbrd.f(3)							      LAPACK							       sgbbrd.f(3)

NAME
sgbbrd.f -

SYNOPSIS
Functions/Subroutines
subroutine sgbbrd (VECT, M, N, NCC, KL, KU, AB, LDAB, D, E, Q, LDQ, PT, LDPT, C, LDC, WORK, INFO)
SGBBRD

Function/Subroutine Documentation
subroutine sgbbrd (characterVECT, integerM, integerN, integerNCC, integerKL, integerKU, real, dimension( ldab, * )AB, integerLDAB, real,
dimension( * )D, real, dimension( * )E, real, dimension( ldq, * )Q, integerLDQ, real, dimension( ldpt, * )PT, integerLDPT, real, dimension(
ldc, * )C, integerLDC, real, dimension( * )WORK, integerINFO)
SGBBRD

Purpose:

SGBBRD reduces a real general m-by-n band matrix A to upper
bidiagonal form B by an orthogonal transformation: Q**T * A * P = B.

The routine computes B, and optionally forms Q or P**T, or computes
Q**T*C for a given matrix C.

Parameters:
VECT

VECT is CHARACTER*1
Specifies whether or not the matrices Q and P**T are to be
formed.
= 'N': do not form Q or P**T;
= 'Q': form Q only;
= 'P': form P**T only;
= 'B': form both.

M

M is INTEGER
The number of rows of the matrix A.  M >= 0.

N

N is INTEGER
The number of columns of the matrix A.  N >= 0.

NCC

NCC is INTEGER
The number of columns of the matrix C.  NCC >= 0.

KL

KL is INTEGER
The number of subdiagonals of the matrix A. KL >= 0.

KU

KU is INTEGER
The number of superdiagonals of the matrix A. KU >= 0.

AB

AB is REAL array, dimension (LDAB,N)
On entry, the m-by-n band matrix A, stored in rows 1 to
KL+KU+1. The j-th column of A is stored in the j-th column of
the array AB as follows:
AB(ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=i<=min(m,j+kl).
On exit, A is overwritten by values generated during the
reduction.

LDAB

LDAB is INTEGER
The leading dimension of the array A. LDAB >= KL+KU+1.

D

D is REAL array, dimension (min(M,N))
The diagonal elements of the bidiagonal matrix B.

E

E is REAL array, dimension (min(M,N)-1)
The superdiagonal elements of the bidiagonal matrix B.

Q

Q is REAL array, dimension (LDQ,M)
If VECT = 'Q' or 'B', the m-by-m orthogonal matrix Q.
If VECT = 'N' or 'P', the array Q is not referenced.

LDQ

LDQ is INTEGER
The leading dimension of the array Q.
LDQ >= max(1,M) if VECT = 'Q' or 'B'; LDQ >= 1 otherwise.

PT

PT is REAL array, dimension (LDPT,N)
If VECT = 'P' or 'B', the n-by-n orthogonal matrix P'.
If VECT = 'N' or 'Q', the array PT is not referenced.

LDPT

LDPT is INTEGER
The leading dimension of the array PT.
LDPT >= max(1,N) if VECT = 'P' or 'B'; LDPT >= 1 otherwise.

C

C is REAL array, dimension (LDC,NCC)
On entry, an m-by-ncc matrix C.
On exit, C is overwritten by Q**T*C.
C is not referenced if NCC = 0.

LDC

LDC is INTEGER
The leading dimension of the array C.
LDC >= max(1,M) if NCC > 0; LDC >= 1 if NCC = 0.

WORK

WORK is REAL array, dimension (2*max(M,N))

INFO

INFO is INTEGER
= 0:  successful exit.
< 0:  if INFO = -i, the i-th argument had an illegal value.

Author:
Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:
November 2011

Definition at line 187 of file sgbbrd.f.

Author
Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2							  Tue Sep 25 2012						       sgbbrd.f(3)```
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