dgetrs (l) - Linux Manuals
dgetrs: solves a system of linear equations A * X = B or Aaq * X = B with a general N-by-N matrix A using the LU factorization computed by DGETRF
NAME
DGETRS - solves a system of linear equations A * X = B or Aaq * X = B with a general N-by-N matrix A using the LU factorization computed by DGETRFSYNOPSIS
- SUBROUTINE DGETRS(
- TRANS, N, NRHS, A, LDA, IPIV, B, LDB, INFO )
- CHARACTER TRANS
- INTEGER INFO, LDA, LDB, N, NRHS
- INTEGER IPIV( * )
- DOUBLE PRECISION A( LDA, * ), B( LDB, * )
PURPOSE
DGETRS solves a system of linear equationsA
ARGUMENTS
- TRANS (input) CHARACTER*1
-
Specifies the form of the system of equations:
= aqNaq: A * X = B (No transpose)
= aqTaq: Aaq* X = B (Transpose)
= aqCaq: Aaq* X = B (Conjugate transpose = Transpose) - N (input) INTEGER
- The order of the matrix A. N >= 0.
- NRHS (input) INTEGER
- The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
- A (input) DOUBLE PRECISION array, dimension (LDA,N)
- The factors L and U from the factorization A = P*L*U as computed by DGETRF.
- LDA (input) INTEGER
- The leading dimension of the array A. LDA >= max(1,N).
- IPIV (input) INTEGER array, dimension (N)
- The pivot indices from DGETRF; for 1<=i<=N, row i of the matrix was interchanged with row IPIV(i).
- B (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
- On entry, the right hand side matrix B. On exit, the solution matrix X.
- LDB (input) INTEGER
- The leading dimension of the array B. LDB >= max(1,N).
- INFO (output) INTEGER
-
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value