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Class org.netlib.lapack.DPPTRF

java.lang.Object
   |
   +----org.netlib.lapack.DPPTRF

public class DPPTRF

extends Object

DPPTRF is a simplified interface to the JLAPACK routine dpptrf.
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
 *  =======
 *
 *  DPPTRF computes the Cholesky factorization of a real symmetric
 *  positive definite matrix A stored in packed format.
 *
 *  The factorization has the form
 *     A = U**T * U,  if UPLO = 'U', or
 *     A = L  * L**T,  if UPLO = 'L',
 *  where U is an upper triangular matrix and L is lower triangular.
 *
 *  Arguments
 *  =========
 *
 *  UPLO    (input) CHARACTER*1
 *          = 'U':  Upper triangle of A is stored;
 *          = 'L':  Lower triangle of A is stored.
 *
 *  N       (input) INTEGER
 *          The order of the matrix A.  N >= 0.
 *
 *  AP      (input/output) DOUBLE PRECISION array, dimension (N*(N+1)/2)
 *          On entry, the upper or lower triangle of the symmetric matrix
 *          A, packed columnwise in a linear array.  The j-th column of A
 *          is stored in the array AP as follows:
 *          if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
 *          if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
 *          See below for further details.
 *
 *          On exit, if INFO = 0, the triangular factor U or L from the
 *          Cholesky factorization A = U**T*U or A = L*L**T, in the same
 *          storage format as A.
 *
 *  INFO    (output) INTEGER
 *          = 0:  successful exit
 *          < 0:  if INFO = -i, the i-th argument had an illegal value
 *          > 0:  if INFO = i, the leading minor of order i is not
 *                positive definite, and the factorization could not be
 *                completed.
 *
 *  Further Details
 *  ======= =======
 *
 *  The packed storage scheme is illustrated by the following example
 *  when N = 4, UPLO = 'U':
 *
 *  Two-dimensional storage of the symmetric matrix A:
 *
 *     a11 a12 a13 a14
 *         a22 a23 a24
 *             a33 a34     (aij = aji)
 *                 a44
 *
 *  Packed storage of the upper triangle of A:
 *
 *  AP = [ a11, a12, a22, a13, a23, a33, a14, a24, a34, a44 ]
 *
 *  =====================================================================
 *
 *     .. Parameters ..

DPPTRF()

DPPTRF(String, int, double[], intW)

 public DPPTRF()

 public static void DPPTRF(String uplo,
                           int n,
                           double ap[],
                           intW info)

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