org.netlib.lapack
Class SGELQF

java.lang.Object
  org.netlib.lapack.SGELQF

public class SGELQF
extends java.lang.Object

SGELQF is a simplified interface to the JLAPACK routine sgelqf.
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
 *  =======
 *
 *  SGELQF computes an LQ factorization of a real M-by-N matrix A:
 *  A = L * Q.
 *
 *  Arguments
 *  =========
 *
 *  M       (input) INTEGER
 *          The number of rows of the matrix A.  M >= 0.
 *
 *  N       (input) INTEGER
 *          The number of columns of the matrix A.  N >= 0.
 *
 *  A       (input/output) REAL array, dimension (LDA,N)
 *          On entry, the M-by-N matrix A.
 *          On exit, the elements on and below the diagonal of the array

 *          contain the m-by-min(m,n) lower trapezoidal matrix L (L is
 *          lower triangular if m <= n); the elements above the diagonal,
 *          with the array TAU, represent the orthogonal matrix Q as a
 *          product of elementary reflectors (see Further Details).
 *
 *  LDA     (input) INTEGER
 *          The leading dimension of the array A.  LDA >= max(1,M).
 *
 *  TAU     (output) REAL array, dimension (min(M,N))
 *          The scalar factors of the elementary reflectors (see Further

 *          Details).
 *
 *  WORK    (workspace/output) REAL 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,M).
 *          For optimum performance LWORK >= M*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
 *
 *  Further Details
 *  ===============
 *
 *  The matrix Q is represented as a product of elementary reflectors
 *
 *     Q = H(k) . . . H(2) H(1), where k = min(m,n).
 *
 *  Each H(i) has the form
 *
 *     H(i) = I - tau * v * v'
 *
 *  where tau is a real scalar, and v is a real vector with
 *  v(1:i-1) = 0 and v(i) = 1; v(i+1:n) is stored on exit in A(i,i+1:n),

 *  and tau in TAU(i).
 *
 *  =====================================================================
 *
 *     .. Local Scalars ..

Constructor Summary

SGELQF()

Method Summary

static void

SGELQF(int m, int n, float[][] a, float[] tau, float[] 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

SGELQF

public SGELQF()

Method Detail

SGELQF

public static void SGELQF(int m,
                          int n,
                          float[][] a,
                          float[] tau,
                          float[] work,
                          int lwork,
                          intW info)