spbt01.f3

!>
!> SPBT01 reconstructs a symmetric positive definite band matrix A from
!> its L*L' or U'*U factorization and computes the residual
!>    norm( L*L' - A ) / ( N * norm(A) * EPS ) or
!>    norm( U'*U - A ) / ( N * norm(A) * EPS ),
!> where EPS is the machine epsilon, L' is the conjugate transpose of
!> L, and U' is the conjugate transpose of U.
!> 

UPLO

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

N

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

KD

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

A

!>          A is REAL array, dimension (LDA,N)
!>          The original symmetric band matrix A.  If UPLO = 'U', the
!>          upper triangular part of A is stored as a band matrix; if
!>          UPLO = 'L', the lower triangular part of A is stored.  The
!>          columns of the appropriate triangle are stored in the columns
!>          of A and the diagonals of the triangle are stored in the rows
!>          of A.  See SPBTRF for further details.
!> 

LDA

!>          LDA is INTEGER.
!>          The leading dimension of the array A.  LDA >= max(1,KD+1).
!> 

AFAC

!>          AFAC is REAL array, dimension (LDAFAC,N)
!>          The factored form of the matrix A.  AFAC contains the factor
!>          L or U from the L*L' or U'*U factorization in band storage
!>          format, as computed by SPBTRF.
!> 

LDAFAC

!>          LDAFAC is INTEGER
!>          The leading dimension of the array AFAC.
!>          LDAFAC >= max(1,KD+1).
!> 

RWORK

!>          RWORK is REAL array, dimension (N)
!> 

RESID

!>          RESID is REAL
!>          If UPLO = 'L', norm(L*L' - A) / ( N * norm(A) * EPS )
!>          If UPLO = 'U', norm(U'*U - A) / ( N * norm(A) * EPS )
!> 

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