table of contents
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dpbcon.f(3) | Library Functions Manual | /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dpbcon.f(3) |
NAME¶
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dpbcon.f
SYNOPSIS¶
Functions/Subroutines¶
subroutine DPBCON (uplo, n, kd, ab, ldab, anorm, rcond,
work, iwork, info)
DPBCON
Function/Subroutine Documentation¶
subroutine DPBCON (character uplo, integer n, integer kd, double precision, dimension( ldab, * ) ab, integer ldab, double precision anorm, double precision rcond, double precision, dimension( * ) work, integer, dimension( * ) iwork, integer info)¶
DPBCON
Purpose:
!> !> DPBCON estimates the reciprocal of the condition number (in the !> 1-norm) of a real symmetric positive definite band matrix using the !> Cholesky factorization A = U**T*U or A = L*L**T computed by DPBTRF. !> !> An estimate is obtained for norm(inv(A)), and the reciprocal of the !> condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))). !>
Parameters
UPLO
!> UPLO is CHARACTER*1 !> = 'U': Upper triangular factor stored in AB; !> = 'L': Lower triangular factor stored in AB. !>
N
!> N is INTEGER !> The order of the matrix A. N >= 0. !>
KD
!> KD is INTEGER !> The number of superdiagonals of the matrix A if UPLO = 'U', !> or the number of subdiagonals if UPLO = 'L'. KD >= 0. !>
AB
!> AB is DOUBLE PRECISION array, dimension (LDAB,N) !> The triangular factor U or L from the Cholesky factorization !> A = U**T*U or A = L*L**T of the band matrix A, stored in the !> first KD+1 rows of the array. The j-th column of U or L is !> stored in the j-th column of the array AB as follows: !> if UPLO ='U', AB(kd+1+i-j,j) = U(i,j) for max(1,j-kd)<=i<=j; !> if UPLO ='L', AB(1+i-j,j) = L(i,j) for j<=i<=min(n,j+kd). !>
LDAB
!> LDAB is INTEGER !> The leading dimension of the array AB. LDAB >= KD+1. !>
ANORM
!> ANORM is DOUBLE PRECISION !> The 1-norm (or infinity-norm) of the symmetric band matrix A. !>
RCOND
!> RCOND is DOUBLE PRECISION !> The reciprocal of the condition number of the matrix A, !> computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an !> estimate of the 1-norm of inv(A) computed in this routine. !>
WORK
!> WORK is DOUBLE PRECISION array, dimension (3*N) !>
IWORK
!> IWORK is INTEGER array, dimension (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
Univ. of Colorado Denver
NAG Ltd.
Definition at line 130 of file dpbcon.f.
Author¶
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Version 3.12.0 | LAPACK |