sdttrf(3) [debian man page]

SDTTRF(l)						   LAPACK routine (version 2.0) 						 SDTTRF(l)

NAME

       SDTTRF - compute an LU factorization of a complex tridiagonal matrix A using elimination without partial pivoting

SYNOPSIS

       SUBROUTINE SDTTRF( N, DL, D, DU, INFO )

	   INTEGER	  INFO, N

	   REAL 	  D( * ), DL( * ), DU( * )

PURPOSE

       SDTTRF computes an LU factorization of a complex tridiagonal matrix A using elimination without partial pivoting.

       The factorization has the form
	  A = L * U
       where L is a product of unit lower bidiagonal
       matrices and U is upper triangular with nonzeros in only the main diagonal and first superdiagonal.

ARGUMENTS

       N       (input) INTEGER
	       The order of the matrix A.  N >= 0.

       DL      (input/output) COMPLEX array, dimension (N-1)
	       On entry, DL must contain the (n-1) subdiagonal elements of A.  On exit, DL is overwritten by the (n-1) multipliers that define the
	       matrix L from the LU factorization of A.

       D       (input/output) COMPLEX array, dimension (N)
	       On entry, D must contain the diagonal elements of A.  On exit, D is overwritten by the n diagonal elements of the upper	triangular
	       matrix U from the LU factorization of A.

       DU      (input/output) COMPLEX array, dimension (N-1)
	       On  entry,  DU  must  contain the (n-1) superdiagonal elements of A.  On exit, DU is overwritten by the (n-1) elements of the first
	       superdiagonal of U.

       INFO    (output) INTEGER
	       = 0:  successful exit
	       < 0:  if INFO = -i, the i-th argument had an illegal value
	       > 0:  if INFO = i, U(i,i) is exactly zero. The factorization has been completed, but the factor U is exactly singular, and division
	       by zero will occur if it is used to solve a system of equations.

modified LAPACK routine 					    12 May 1997 							 SDTTRF(l)

CGTTRF(l)								 )								 CGTTRF(l)

NAME

       CGTTRF - compute an LU factorization of a complex tridiagonal matrix A using elimination with partial pivoting and row interchanges

SYNOPSIS

       SUBROUTINE CGTTRF( N, DL, D, DU, DU2, IPIV, INFO )

	   INTEGER	  INFO, N

	   INTEGER	  IPIV( * )

	   COMPLEX	  D( * ), DL( * ), DU( * ), DU2( * )

PURPOSE

       CGTTRF  computes  an  LU factorization of a complex tridiagonal matrix A using elimination with partial pivoting and row interchanges.  The
       factorization has the form
	  A = L * U
       where L is a product of permutation and unit lower bidiagonal matrices and U is upper triangular with nonzeros in only  the  main  diagonal
       and first two superdiagonals.

ARGUMENTS

       N       (input) INTEGER
	       The order of the matrix A.

       DL      (input/output) COMPLEX array, dimension (N-1)
	       On entry, DL must contain the (n-1) sub-diagonal elements of A.

	       On exit, DL is overwritten by the (n-1) multipliers that define the matrix L from the LU factorization of A.

       D       (input/output) COMPLEX array, dimension (N)
	       On entry, D must contain the diagonal elements of A.

	       On exit, D is overwritten by the n diagonal elements of the upper triangular matrix U from the LU factorization of A.

       DU      (input/output) COMPLEX array, dimension (N-1)
	       On entry, DU must contain the (n-1) super-diagonal elements of A.

	       On exit, DU is overwritten by the (n-1) elements of the first super-diagonal of U.

       DU2     (output) COMPLEX array, dimension (N-2)
	       On exit, DU2 is overwritten by the (n-2) elements of the second super-diagonal of U.

       IPIV    (output) 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.

       INFO    (output) INTEGER
	       = 0:  successful exit
	       < 0:  if INFO = -k, the k-th argument had an illegal value
	       > 0:  if INFO = k, U(k,k) is exactly zero. The factorization has been completed, but the factor U is exactly singular, and division
	       by zero will occur if it is used to solve a system of equations.

LAPACK version 3.0						   15 June 2000 							 CGTTRF(l)