dgtts2.f3
Usage
Functions/Subroutines
subroutine dgtts2 (itrans, n, nrhs, dl, d, du, du2, ipiv, b, ldb)
DGTTS2 solves a system of linear equations with a tridiagonal matrix using the LU factorization computed by sgttrf.
Function/Subroutine Documentation
subroutine dgtts2 (integer itrans, integer n, integer nrhs, double precision, dimension( * ) dl, double precision, dimension( * ) d, double precision, dimension( * ) du, double precision, dimension( * ) du2, integer, dimension( * ) ipiv, double precision, dimension( ldb, * ) b, integer ldb)
DGTTS2 solves a system of linear equations with a tridiagonal matrix using the LU factorization computed by sgttrf.
Purpose:
!> !> DGTTS2 solves one of the systems of equations !> A*X = B or A**T*X = B, !> with a tridiagonal matrix A using the LU factorization computed !> by DGTTRF. !>
Parameters
ITRANS
!> ITRANS is INTEGER !> Specifies the form of the system of equations. !> = 0: A * X = B (No transpose) !> = 1: A**T* X = B (Transpose) !> = 2: A**T* X = B (Conjugate transpose = Transpose) !>
N
!> N is INTEGER !> The order of the matrix A. !>
NRHS
!> NRHS is INTEGER !> The number of right hand sides, i.e., the number of columns !> of the matrix B. NRHS >= 0. !>
DL
!> DL is DOUBLE PRECISION array, dimension (N-1) !> The (n-1) multipliers that define the matrix L from the !> LU factorization of A. !>
D
!> D is DOUBLE PRECISION array, dimension (N) !> The n diagonal elements of the upper triangular matrix U from !> the LU factorization of A. !>
DU
!> DU is DOUBLE PRECISION array, dimension (N-1) !> The (n-1) elements of the first super-diagonal of U. !>
DU2
!> DU2 is DOUBLE PRECISION array, dimension (N-2) !> The (n-2) elements of the second super-diagonal of U. !>
IPIV
!> IPIV is INTEGER array, dimension (N) !> The pivot indices; for 1 <= i <= n, row i of the matrix was !> interchanged with row IPIV(i). IPIV(i) will always be either !> i or i+1; IPIV(i) = i indicates a row interchange was not !> required. !>
B
!> B is DOUBLE PRECISION array, dimension (LDB,NRHS) !> On entry, the matrix of right hand side vectors B. !> On exit, B is overwritten by the solution vectors X. !>
LDB
!> LDB is INTEGER !> The leading dimension of the array B. LDB >= max(1,N). !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 127 of file dgtts2.f.
Releases
4 releases since Debian 7 (Wheezy); the text changed 3 times.