NAME

SYNOPSIS

  SUBROUTINE SGBTF2( M, N, KL, KU, AB, LDAB, IPIV, INFO)
  INTEGER M, N, KL, KU, LDAB, INFO
  INTEGER IPIV(*)
  REAL AB(LDAB,*)
 
  SUBROUTINE SGBTF2_64( M, N, KL, KU, AB, LDAB, IPIV, INFO)
  INTEGER*8 M, N, KL, KU, LDAB, INFO
  INTEGER*8 IPIV(*)
  REAL AB(LDAB,*)
 

F95 INTERFACE

  SUBROUTINE GBTF2( [M], [N], KL, KU, AB, [LDAB], IPIV, [INFO])
  INTEGER :: M, N, KL, KU, LDAB, INFO
  INTEGER, DIMENSION(:) :: IPIV
  REAL, DIMENSION(:,:) :: AB
 
  SUBROUTINE GBTF2_64( [M], [N], KL, KU, AB, [LDAB], IPIV, [INFO])
  INTEGER(8) :: M, N, KL, KU, LDAB, INFO
  INTEGER(8), DIMENSION(:) :: IPIV
  REAL, DIMENSION(:,:) :: AB
 

C INTERFACE

void sgbtf2(int m, int n, int kl, int ku, float *ab, int ldab, int *ipiv, int *info);

void sgbtf2_64(long m, long n, long kl, long ku, float *ab, long ldab, long *ipiv, long *info);

PURPOSE

This is the unblocked version of the algorithm, calling Level 2 BLAS.

ARGUMENTS

* M (input)

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

* N (input)

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

* KL (input)

The number of subdiagonals within the band of A. KL >= 0.

* KU (input)

The number of superdiagonals within the band of A. KU >= 0.

* AB (input/output)

On entry, the matrix A in band storage, in rows KL+1 to 2*KL+KU+1; rows 1 to KL of the array need not be set. The j-th column of A is stored in the j-th column of the array AB as follows: AB(kl+ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=i<=min(m,j+kl)

On exit, details of the factorization: U is stored as an upper triangular band matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, and the multipliers used during the factorization are stored in rows KL+KU+2 to 2*KL+KU+1. See below for further details.

* LDAB (input)

The leading dimension of the array AB. LDAB >= 2*KL+KU+1.

* IPIV (output)

The pivot indices; for 1 <= i <= min(M,N), row i of the matrix was interchanged with row IPIV(i).

* INFO (output)