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LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
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subroutine dgbt02 | ( | character | TRANS, |
integer | M, | ||
integer | N, | ||
integer | KL, | ||
integer | KU, | ||
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 | RESID | ||
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DGBT02
DGBT02 computes the residual for a solution of a banded system of equations A*x = b or A'*x = b: RESID = norm( B - A*X ) / ( norm(A) * norm(X) * EPS). where EPS is the machine precision.
[in] | TRANS | TRANS is CHARACTER*1 Specifies the form of the system of equations: = 'N': A *x = b = 'T': A'*x = b, where A' is the transpose of A = 'C': A'*x = b, where A' is the transpose of A |
[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 DOUBLE PRECISION 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 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. If TRANS = 'N', LDX >= max(1,N); if TRANS = 'T' or 'C', LDX >= max(1,M). |
[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. IF TRANS = 'N', LDB >= max(1,M); if TRANS = 'T' or 'C', LDB >= max(1,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 141 of file dgbt02.f.