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LAPACK version 3.0
dpttrs(3)

PURPOSE
  DPTTRS - solve a tridiagonal system of the form A * X = B using the L*D*L'
  factorization of A computed by DPTTRF

SYNTAX
  SUBROUTINE DPTTRS( N, NRHS, D, E, B, LDB, INFO )

      INTEGER	     INFO, LDB, N, NRHS

      DOUBLE	     PRECISION B( LDB, * ), D( * ), E( * )

DESCRIPTION
  DPTTRS solves a tridiagonal system of the form A * X = B using the L*D*L'
  factorization of A computed by DPTTRF. D is a diagonal matrix specified in
  the vector D, L is a unit bidiagonal matrix whose subdiagonal is specified
  in the vector E, and X and B are N by NRHS matrices.

ARGUMENTS
  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) DOUBLE PRECISION array, dimension (N)
	  The n diagonal elements of the diagonal matrix D from the L*D*L'
	  factorization of A.

  E	  (input) DOUBLE PRECISION array, dimension (N-1)
	  The (n-1) subdiagonal elements of the unit bidiagonal factor L from
	  the L*D*L' factorization of A.  E can also be regarded as the
	  superdiagonal of the unit bidiagonal factor U from the
	  factorization A = U'*D*U.

  B	  (input/output) DOUBLE PRECISION 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