org.netlib.lapack
Class DORGTR

java.lang.Object
  org.netlib.lapack.DORGTR

public class DORGTR
extends java.lang.Object

DORGTR is a simplified interface to the JLAPACK routine dorgtr.
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
 *  =======
 *
 *  DORGTR generates a real orthogonal matrix Q which is defined as the
 *  product of n-1 elementary reflectors of order N, as returned by
 *  DSYTRD:
 *
 *  if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),
 *
 *  if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).
 *
 *  Arguments
 *  =========
 *
 *  UPLO    (input) CHARACTER*1
 *          = 'U': Upper triangle of A contains elementary reflectors
 *                 from DSYTRD;
 *          = 'L': Lower triangle of A contains elementary reflectors
 *                 from DSYTRD.
 *
 *  N       (input) INTEGER
 *          The order of the matrix Q. N >= 0.
 *
 *  A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
 *          On entry, the vectors which define the elementary reflectors,
 *          as returned by DSYTRD.
 *          On exit, the N-by-N orthogonal matrix Q.
 *
 *  LDA     (input) INTEGER
 *          The leading dimension of the array A. LDA >= max(1,N).
 *
 *  TAU     (input) DOUBLE PRECISION array, dimension (N-1)
 *          TAU(i) must contain the scalar factor of the elementary
 *          reflector H(i), as returned by DSYTRD.
 *
 *  WORK    (workspace/output) DOUBLE PRECISION array, dimension (LWORK)

 *          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
 *
 *  LWORK   (input) INTEGER
 *          The dimension of the array WORK. LWORK >= max(1,N-1).
 *          For optimum performance LWORK >= (N-1)*NB, where NB is
 *          the optimal blocksize.
 *
 *          If LWORK = -1, then a workspace query is assumed; the routine
 *          only calculates the optimal size of the WORK array, returns
 *          this value as the first entry of the WORK array, and no error
 *          message related to LWORK is issued by XERBLA.
 *
 *  INFO    (output) INTEGER
 *          = 0:  successful exit
 *          < 0:  if INFO = -i, the i-th argument had an illegal value
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

DORGTR()

Method Summary

static void

DORGTR(java.lang.String uplo, int n, double[][] a, double[] tau, double[] work, int lwork, intW info)

Methods inherited from class java.lang.Object

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

Constructor Detail

DORGTR

public DORGTR()

Method Detail

DORGTR

public static void DORGTR(java.lang.String uplo,
                          int n,
                          double[][] a,
                          double[] tau,
                          double[] work,
                          int lwork,
                          intW info)