All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class org.netlib.lapack.DTPTRI

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

public class DTPTRI

extends Object

DTPTRI is a simplified interface to the JLAPACK routine dtptri.
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
 *  =======
 *
 *  DTPTRI computes the inverse of a real upper or lower triangular
 *  matrix A stored in packed format.
 *
 *  Arguments
 *  =========
 *
 *  UPLO    (input) CHARACTER*1
 *          = 'U':  A is upper triangular;
 *          = 'L':  A is lower triangular.
 *
 *  DIAG    (input) CHARACTER*1
 *          = 'N':  A is non-unit triangular;
 *          = 'U':  A is unit triangular.
 *
 *  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 triangular matrix A, stored
 *          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)*((2*n-j)/2) = A(i,j) for j<=i<=n.
 *          See below for further details.
 *          On exit, the (triangular) inverse of the original matrix, in
 *          the same packed storage format.
 *
 *  INFO    (output) INTEGER
 *          = 0:  successful exit
 *          < 0:  if INFO = -i, the i-th argument had an illegal value
 *          > 0:  if INFO = i, A(i,i) is exactly zero.  The triangular
 *                matrix is singular and its inverse can not be computed.
 *
 *  Further Details
 *  ===============
 *
 *  A triangular matrix A can be transferred to packed storage using one
 *  of the following program segments:
 *
 *  UPLO = 'U':                      UPLO = 'L':
 *
 *        JC = 1                           JC = 1
 *        DO 2 J = 1, N                    DO 2 J = 1, N
 *           DO 1 I = 1, J                    DO 1 I = J, N
 *              AP(JC+I-1) = A(I,J)              AP(JC+I-J) = A(I,J)
 *      1    CONTINUE                    1    CONTINUE
 *           JC = JC + J                      JC = JC + N - J + 1
 *      2 CONTINUE                       2 CONTINUE
 *
 *  =====================================================================
 *
 *     .. Parameters ..

DTPTRI()

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

 public DTPTRI()

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

All Packages  Class Hierarchy  This Package  Previous  Next  Index