dgtts2 - solve a system of linear equations with a tridiagonal matrix using the LU factorization computed by dgttrf
SUBROUTINE DGTTS2(ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB) INTEGER ITRANS, LDB, N, NRHS INTEGER IPIV(*) DOUBLE PRECISION B(LDB,*), D(*), DL(*), DU(*), DU2(*) SUBROUTINE DGTTS2_64(ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB) INTEGER*8 ITRANS, LDB, N, NRHS INTEGER*8 IPIV(*) DOUBLE PRECISION B(LDB,*), D(*), DL(*), DU(*), DU2(*) F95 INTERFACE SUBROUTINE GTTS2(ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB) REAL(8), DIMENSION(:,:) :: B INTEGER :: ITRANS, N, NRHS, LDB INTEGER, DIMENSION(:) :: IPIV REAL(8), DIMENSION(:) :: DL, D, DU, DU2 SUBROUTINE GTTS2_64(ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB) REAL(8), DIMENSION(:,:) :: B INTEGER(8) :: ITRANS, N, NRHS, LDB INTEGER(8), DIMENSION(:) :: IPIV REAL(8), DIMENSION(:) :: DL, D, DU, DU2 C INTERFACE #include <sunperf.h> void dgtts2 (int itrans, int n, int nrhs, double *dl, double *d, double *du, double *du2, int *ipiv, double *b, int ldb); void dgtts2_64 (long itrans, long n, long nrhs, double *dl, double *d, double *du, double *du2, long *ipiv, double *b, long ldb);
Oracle Solaris Studio Performance Library dgtts2(3P) NAME dgtts2 - solve a system of linear equations with a tridiagonal matrix using the LU factorization computed by dgttrf SYNOPSIS SUBROUTINE DGTTS2(ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB) INTEGER ITRANS, LDB, N, NRHS INTEGER IPIV(*) DOUBLE PRECISION B(LDB,*), D(*), DL(*), DU(*), DU2(*) SUBROUTINE DGTTS2_64(ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB) INTEGER*8 ITRANS, LDB, N, NRHS INTEGER*8 IPIV(*) DOUBLE PRECISION B(LDB,*), D(*), DL(*), DU(*), DU2(*) F95 INTERFACE SUBROUTINE GTTS2(ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB) REAL(8), DIMENSION(:,:) :: B INTEGER :: ITRANS, N, NRHS, LDB INTEGER, DIMENSION(:) :: IPIV REAL(8), DIMENSION(:) :: DL, D, DU, DU2 SUBROUTINE GTTS2_64(ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB) REAL(8), DIMENSION(:,:) :: B INTEGER(8) :: ITRANS, N, NRHS, LDB INTEGER(8), DIMENSION(:) :: IPIV REAL(8), DIMENSION(:) :: DL, D, DU, DU2 C INTERFACE #include <sunperf.h> void dgtts2 (int itrans, int n, int nrhs, double *dl, double *d, double *du, double *du2, int *ipiv, double *b, int ldb); void dgtts2_64 (long itrans, long n, long nrhs, double *dl, double *d, double *du, double *du2, long *ipiv, double *b, long ldb); 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. ARGUMENTS ITRANS (input) 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 (input) N is INTEGER The order of the matrix A. NRHS (input) NRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0. DL (input) DL is DOUBLE PRECISION array, dimension (N-1) The (N-1) multipliers that define the matrix L from the LU factorization of A. D (input) D is DOUBLE PRECISION array, dimension (N) The N diagonal elements of the upper triangular matrix U from the LU factorization of A. DU (input) DU is DOUBLE PRECISION array, dimension (N-1) The (N-1) elements of the first super-diagonal of U. DU2 (input) DU2 is DOUBLE PRECISION array, dimension (N-2) The (N-2) elements of the second super-diagonal of U. IPIV (input) 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 (input/output) 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 (input) LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N). 7 Nov 2015 dgtts2(3P)