PLASMA: PLASMA_dsgesv

PLASMA 2.4.6

- Main Page
- Modules
- Data Types List

All Data Structures Functions Groups

PLASMA_dgebrd
PLASMA_dgelqf
PLASMA_dgelqs
PLASMA_dgels
PLASMA_dgemm
PLASMA_dgeqrf
PLASMA_dgeqrs
PLASMA_dgesv
PLASMA_dgesv_incpiv
PLASMA_dgesvd
PLASMA_dgetrf
PLASMA_dgetrf_incpiv
PLASMA_dgetri
PLASMA_dgetrs
PLASMA_dgetrs_incpiv
PLASMA_dlacpy
PLASMA_dlange
PLASMA_dlansy
PLASMA_dLapack_to_Tile
PLASMA_dlaset
PLASMA_dlaswp
PLASMA_dlaswpc
PLASMA_dlauum
PLASMA_dorglq
PLASMA_dorgqr
PLASMA_dormlq
PLASMA_dormqr
PLASMA_dplgsy
PLASMA_dplrnt
PLASMA_dposv
PLASMA_dpotrf
PLASMA_dpotri
PLASMA_dpotrs
PLASMA_dsgesv
PLASMA_dsposv
PLASMA_dsungesv
PLASMA_dsyev
PLASMA_dsyevd
PLASMA_dsygst
PLASMA_dsygv
PLASMA_dsygvd
PLASMA_dsymm
PLASMA_dsyr2k
PLASMA_dsyrk
PLASMA_dsytrd
PLASMA_dTile_to_Lapack
PLASMA_dtrmm
PLASMA_dtrsm
PLASMA_dtrsmpl
PLASMA_dtrsmrv
PLASMA_dtrtri
int PLASMA_dsgesv | ( | int | N,
|  | int | NRHS,
|  | double * | A,
|  | int | LDA,
|  | int * | IPIV,
|  | double * | B,
|  | int | LDB,
|  | double * | X,
|  | int | LDX,
|  | int * | ITER
| ) |  |
  PLASMA_dsgesv - Computes the solution to a system of linear equations A * X = B, where A is an N-by-N matrix and X and B are N-by-NRHS matrices. PLASMA_dsgesv first attempts to factorize the matrix in COMPLEX and use this factorization within an iterative refinement procedure to produce a solution with COMPLEX*16 normwise backward error quality (see below). If the approach fails the method switches to a COMPLEX*16 factorization and solve. The iterative refinement is not going to be a winning strategy if the ratio COMPLEX performance over COMPLEX*16 performance is too small. A reasonable strategy should take the number of right-hand sides and the size of the matrix into account. This might be done with a call to ILAENV in the future. Up to now, we always try iterative refinement. The iterative refinement process is stopped if ITER > ITERMAX or for all the RHS we have: RNRM < N*XNRM*ANRM*EPS*BWDMAX where: ITER is the number of the current iteration in the iterative refinement process RNRM is the infinity-norm of the residual XNRM is the infinity-norm of the solution ANRM is the infinity-operator-norm of the matrix A EPS is the machine epsilon returned by DLAMCH('Epsilon'). Actually, in its current state (PLASMA 2.1.0), the test is slightly relaxed. The values ITERMAX and BWDMAX are fixed to 30 and 1.0D+00 respectively. Parameters
  [in] | N | The number of linear equations, i.e., the order of the matrix A. N >= 0.
  [in] | NRHS | The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
  [in] | A | The N-by-N coefficient matrix A. This matrix is not modified.
  [in] | LDA | The leading dimension of the array A. LDA >= max(1,N).
  [out] | IPIV | On exit, the pivot indices that define the permutations.
  [in] | B | The N-by-NRHS matrix of right hand side matrix B.
  [in] | LDB | The leading dimension of the array B. LDB >= max(1,N).
  [out] | X | If return value = 0, the N-by-NRHS solution matrix X.
  [in] | LDX | The leading dimension of the array B. LDX >= max(1,N).
  [out] | ITER | The number of the current iteration in the iterative refinement process
  Returns Return values
  PLASMA_SUCCESS | successful exit
  <0 | if -i, the i-th argument had an illegal value
  >0 | if i, U(i,i) is exactly zero. The factorization has been completed, but the factor U is exactly singular, so the solution could not be computed.
See Also PLASMA_dsgesv_Tile PLASMA_dsgesv_Tile_Async PLASMA_dsgesv PLASMA_dgesv