TESTING/LIN/spbt01.f(3) Library Functions Manual TESTING/LIN/spbt01.f(3) NAME TESTING/LIN/spbt01.f SYNOPSIS Functions/Subroutines subroutine spbt01 (uplo, n, kd, a, lda, afac, ldafac, rwork, resid) SPBT01 Function/Subroutine Documentation subroutine spbt01 (character uplo, integer n, integer kd, real, dimension( lda, * ) a, integer lda, real, dimension( ldafac, * ) afac, integer ldafac, real, dimension( * ) rwork, real resid) SPBT01 Purpose: 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. Parameters 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 ) Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Definition at line 117 of file spbt01.f. Author Generated automatically by Doxygen for LAPACK from the source code. LAPACK Version 3.12.0 TESTING/LIN/spbt01.f(3)