LAPACK 3.12.1
LAPACK: Linear Algebra PACKage
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subroutine dppt02 | ( | character | uplo, |
integer | n, | ||
integer | nrhs, | ||
double precision, dimension( * ) | a, | ||
double precision, dimension( ldx, * ) | x, | ||
integer | ldx, | ||
double precision, dimension( ldb, * ) | b, | ||
integer | ldb, | ||
double precision, dimension( * ) | rwork, | ||
double precision | resid ) |
DPPT02
!> !> DPPT02 computes the residual in the solution of a symmetric system !> of linear equations A*x = b when packed storage is used for the !> coefficient matrix. The ratio computed is !> !> RESID = norm(B - A*X) / ( norm(A) * norm(X) * EPS), !> !> where EPS is the machine precision. !>
[in] | 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 !> |
[in] | N | !> N is INTEGER !> The number of rows and columns of the matrix A. N >= 0. !> |
[in] | NRHS | !> NRHS is INTEGER !> The number of columns of B, the matrix of right hand sides. !> NRHS >= 0. !> |
[in] | A | !> A is DOUBLE PRECISION array, dimension (N*(N+1)/2) !> The original symmetric matrix A, stored as a packed !> triangular matrix. !> |
[in] | X | !> X is DOUBLE PRECISION array, dimension (LDX,NRHS) !> The computed solution vectors for the system of linear !> equations. !> |
[in] | LDX | !> LDX is INTEGER !> The leading dimension of the array X. LDX >= max(1,N). !> |
[in,out] | 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. !> |
[in] | LDB | !> LDB is INTEGER !> The leading dimension of the array B. LDB >= max(1,N). !> |
[out] | RWORK | !> RWORK is DOUBLE PRECISION array, dimension (N) !> |
[out] | RESID | !> RESID is DOUBLE PRECISION !> The maximum over the number of right hand sides of !> norm(B - A*X) / ( norm(A) * norm(X) * EPS ). !> |
Definition at line 120 of file dppt02.f.