dpot06.f3
Usage
Functions/Subroutines
subroutine dpot06 (uplo, n, nrhs, a, lda, x, ldx, b, ldb, rwork, resid)
DPOT06
Function/Subroutine Documentation
subroutine dpot06 (character uplo, integer n, integer nrhs, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldx, * ) x, integer ldx, double precision, dimension( ldb, * ) b, integer ldb, double precision, dimension( * ) rwork, double precision resid)
DPOT06
Purpose:
!> !> DPOT06 computes the residual for a solution of a system of linear !> equations A*x = b : !> RESID = norm(B - A*X,inf) / ( norm(A,inf) * norm(X,inf) * EPS ), !> where EPS is the machine epsilon. !>
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. !>
NRHS
!> NRHS is INTEGER !> The number of columns of B, the matrix of right hand sides. !> NRHS >= 0. !>
A
!> A is DOUBLE PRECISION array, dimension (LDA,N) !> The original M x N matrix A. !>
LDA
!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
X
!> X is DOUBLE PRECISION array, dimension (LDX,NRHS) !> The computed solution vectors for the system of linear !> equations. !>
LDX
!> LDX is INTEGER !> The leading dimension of the array X. If TRANS = 'N', !> LDX >= max(1,N); if TRANS = 'T' or 'C', LDX >= max(1,N). !>
B
!> B is DOUBLE PRECISION array, dimension (LDB,NRHS) !> On entry, the right hand side vectors for the system of !> linear equations. !> On exit, B is overwritten with the difference B - A*X. !>
LDB
!> LDB is INTEGER !> The leading dimension of the array B. IF TRANS = 'N', !> LDB >= max(1,M); if TRANS = 'T' or 'C', LDB >= max(1,N). !>
RWORK
!> RWORK is DOUBLE PRECISION array, dimension (N) !>
RESID
!> RESID is DOUBLE PRECISION !> The maximum over the number of right hand sides of !> norm(B - A*X) / ( norm(A) * norm(X) * EPS ). !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 125 of file dpot06.f.