![]() |
LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
|
subroutine cgbt02 | ( | character | trans, |
integer | m, | ||
integer | n, | ||
integer | kl, | ||
integer | ku, | ||
integer | nrhs, | ||
complex, dimension( lda, * ) | a, | ||
integer | lda, | ||
complex, dimension( ldx, * ) | x, | ||
integer | ldx, | ||
complex, dimension( ldb, * ) | b, | ||
integer | ldb, | ||
real, dimension( * ) | rwork, | ||
real | resid | ||
) |
CGBT02
CGBT02 computes the residual for a solution of a banded system of equations op(A)*X = B: RESID = norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS ), where op(A) = A, A**T, or A**H, depending on TRANS, and EPS is the machine epsilon.
[in] | TRANS | TRANS is CHARACTER*1 Specifies the form of the system of equations: = 'N': A * X = B (No transpose) = 'T': A**T * X = B (Transpose) = 'C': A**H * X = B (Conjugate transpose) |
[in] | M | M is INTEGER The number of rows of the matrix A. M >= 0. |
[in] | N | N is INTEGER The number of columns of the matrix A. N >= 0. |
[in] | KL | KL is INTEGER The number of subdiagonals within the band of A. KL >= 0. |
[in] | KU | KU is INTEGER The number of superdiagonals within the band of A. KU >= 0. |
[in] | NRHS | NRHS is INTEGER The number of columns of B. NRHS >= 0. |
[in] | A | A is COMPLEX array, dimension (LDA,N) The original matrix A in band storage, stored in rows 1 to KL+KU+1. |
[in] | LDA | LDA is INTEGER The leading dimension of the array A. LDA >= max(1,KL+KU+1). |
[in] | X | X is COMPLEX 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. If TRANS = 'N', LDX >= max(1,N); if TRANS = 'T' or 'C', LDX >= max(1,M). |
[in,out] | B | B is COMPLEX 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. IF TRANS = 'N', LDB >= max(1,M); if TRANS = 'T' or 'C', LDB >= max(1,N). |
[out] | RWORK | RWORK is REAL array, dimension (MAX(1,LRWORK)), where LRWORK >= M when TRANS = 'T' or 'C'; otherwise, RWORK is not referenced. |
[out] | RESID | RESID is REAL The maximum over the number of right hand sides of norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS ). |
Definition at line 146 of file cgbt02.f.