org.netlib.lapack
Class SGTTRF

java.lang.Object
  org.netlib.lapack.SGTTRF

public class SGTTRF
extends java.lang.Object

SGTTRF is a simplified interface to the JLAPACK routine sgttrf.
This interface converts Java-style 2D row-major arrays into
the 1D column-major linearized arrays expected by the lower
level JLAPACK routines.  Using this interface also allows you
to omit offset and leading dimension arguments.  However, because
of these conversions, these routines will be slower than the low
level ones.  Following is the description from the original Fortran
source.  Contact seymour@cs.utk.edu with any questions.

 *     ..
 *
 *  Purpose
 *  =======
 *
 *  SGTTRF computes an LU factorization of a real 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) REAL 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) REAL 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) REAL 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) REAL 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.
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

SGTTRF()

Method Summary

static void

SGTTRF(int n, float[] dl, float[] d, float[] du, float[] du2, int[] ipiv, intW info)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SGTTRF

public SGTTRF()

Method Detail

SGTTRF

public static void SGTTRF(int n,
                          float[] dl,
                          float[] d,
                          float[] du,
                          float[] du2,
                          int[] ipiv,
                          intW info)