cpttrs (l) - Linux Manuals
cpttrs: solves a tridiagonal system of the form A * X = B using the factorization A = Uaq*D*U or A = L*D*Laq computed by CPTTRF
NAME
CPTTRS - solves a tridiagonal system of the form A * X = B using the factorization A = Uaq*D*U or A = L*D*Laq computed by CPTTRFSYNOPSIS
- SUBROUTINE CPTTRS(
- UPLO, N, NRHS, D, E, B, LDB, INFO )
- CHARACTER UPLO
- INTEGER INFO, LDB, N, NRHS
- REAL D( * )
- COMPLEX B( LDB, * ), E( * )
PURPOSE
CPTTRS solves a tridiagonal system of the formA
ARGUMENTS
- UPLO (input) CHARACTER*1
-
Specifies the form of the factorization and whether the
vector E is the superdiagonal of the upper bidiagonal factor
U or the subdiagonal of the lower bidiagonal factor L.
= aqUaq: A = Uaq*D*U, E is the superdiagonal of U
= aqLaq: A = L*D*Laq, E is the subdiagonal of L - N (input) INTEGER
- The order of the tridiagonal 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.
- D (input) REAL array, dimension (N)
- The n diagonal elements of the diagonal matrix D from the factorization A = Uaq*D*U or A = L*D*Laq.
- E (input) COMPLEX array, dimension (N-1)
- If UPLO = aqUaq, the (n-1) superdiagonal elements of the unit bidiagonal factor U from the factorization A = Uaq*D*U. If UPLO = aqLaq, the (n-1) subdiagonal elements of the unit bidiagonal factor L from the factorization A = L*D*Laq.
- B (input/output) REAL array, dimension (LDB,NRHS)
- On entry, the right hand side vectors B for the system of linear equations. On exit, the solution vectors, X.
- LDB (input) INTEGER
- The leading dimension of the array B. LDB >= max(1,N).
- INFO (output) INTEGER
-
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value