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LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
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subroutine dlavsp | ( | character | UPLO, |
character | TRANS, | ||
character | DIAG, | ||
integer | N, | ||
integer | NRHS, | ||
double precision, dimension( * ) | A, | ||
integer, dimension( * ) | IPIV, | ||
double precision, dimension( ldb, * ) | B, | ||
integer | LDB, | ||
integer | INFO | ||
) |
DLAVSP
DLAVSP performs one of the matrix-vector operations x := A*x or x := A'*x, where x is an N element vector and A is one of the factors from the block U*D*U' or L*D*L' factorization computed by DSPTRF. If TRANS = 'N', multiplies by U or U * D (or L or L * D) If TRANS = 'T', multiplies by U' or D * U' (or L' or D * L' ) If TRANS = 'C', multiplies by U' or D * U' (or L' or D * L' )
[in] | UPLO | UPLO is CHARACTER*1 Specifies whether the factor stored in A is upper or lower triangular. = 'U': Upper triangular = 'L': Lower triangular |
[in] | TRANS | TRANS is CHARACTER*1 Specifies the operation to be performed: = 'N': x := A*x = 'T': x := A'*x = 'C': x := A'*x |
[in] | DIAG | DIAG is CHARACTER*1 Specifies whether or not the diagonal blocks are unit matrices. If the diagonal blocks are assumed to be unit, then A = U or A = L, otherwise A = U*D or A = L*D. = 'U': Diagonal blocks are assumed to be unit matrices. = 'N': Diagonal blocks are assumed to be non-unit matrices. |
[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 right hand sides, i.e., the number of vectors x to be multiplied by A. NRHS >= 0. |
[in] | A | A is DOUBLE PRECISION array, dimension (N*(N+1)/2) The block diagonal matrix D and the multipliers used to obtain the factor U or L, stored as a packed triangular matrix as computed by DSPTRF. |
[in] | IPIV | IPIV is INTEGER array, dimension (N) The pivot indices from DSPTRF. |
[in,out] | B | B is DOUBLE PRECISION array, dimension (LDB,NRHS) On entry, B contains NRHS vectors of length N. On exit, B is overwritten with the product A * B. |
[in] | LDB | LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N). |
[out] | INFO | INFO is INTEGER = 0: successful exit < 0: if INFO = -k, the k-th argument had an illegal value |
Definition at line 132 of file dlavsp.f.