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Class org.netlib.lapack.Dlarft

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

public class Dlarft

extends Object

Following is the description from the original
Fortran source.  For each array argument, the Java
version will include an integer offset parameter, so
the arguments may not match the description exactly.
Contact seymour@cs.utk.edu with any questions.

 *     ..
 *
 *  Purpose
 *  =======
 *
 *  DLARFT forms the triangular factor T of a real block reflector H
 *  of order n, which is defined as a product of k elementary reflectors.
 *
 *  If DIRECT = 'F', H = H(1) H(2) . . . H(k) and T is upper triangular;
 *
 *  If DIRECT = 'B', H = H(k) . . . H(2) H(1) and T is lower triangular.
 *
 *  If STOREV = 'C', the vector which defines the elementary reflector
 *  H(i) is stored in the i-th column of the array V, and
 *
 *     H  =  I - V * T * V'
 *
 *  If STOREV = 'R', the vector which defines the elementary reflector
 *  H(i) is stored in the i-th row of the array V, and
 *
 *     H  =  I - V' * T * V
 *
 *  Arguments
 *  =========
 *
 *  DIRECT  (input) CHARACTER*1
 *          Specifies the order in which the elementary reflectors are
 *          multiplied to form the block reflector:
 *          = 'F': H = H(1) H(2) . . . H(k) (Forward)
 *          = 'B': H = H(k) . . . H(2) H(1) (Backward)
 *
 *  STOREV  (input) CHARACTER*1
 *          Specifies how the vectors which define the elementary
 *          reflectors are stored (see also Further Details):
 *          = 'C': columnwise
 *          = 'R': rowwise
 *
 *  N       (input) INTEGER
 *          The order of the block reflector H. N >= 0.
 *
 *  K       (input) INTEGER
 *          The order of the triangular factor T (= the number of
 *          elementary reflectors). K >= 1.
 *
 *  V       (input/output) DOUBLE PRECISION array, dimension
 *                               (LDV,K) if STOREV = 'C'
 *                               (LDV,N) if STOREV = 'R'
 *          The matrix V. See further details.
 *
 *  LDV     (input) INTEGER
 *          The leading dimension of the array V.
 *          If STOREV = 'C', LDV >= max(1,N); if STOREV = 'R', LDV >= K.
 *
 *  TAU     (input) DOUBLE PRECISION array, dimension (K)
 *          TAU(i) must contain the scalar factor of the elementary
 *          reflector H(i).
 *
 *  T       (output) DOUBLE PRECISION array, dimension (LDT,K)
 *          The k by k triangular factor T of the block reflector.
 *          If DIRECT = 'F', T is upper triangular; if DIRECT = 'B', T is
 *          lower triangular. The rest of the array is not used.
 *
 *  LDT     (input) INTEGER
 *          The leading dimension of the array T. LDT >= K.
 *
 *  Further Details
 *  ===============
 *
 *  The shape of the matrix V and the storage of the vectors which define
 *  the H(i) is best illustrated by the following example with n = 5 and
 *  k = 3. The elements equal to 1 are not stored; the corresponding
 *  array elements are modified but restored on exit. The rest of the
 *  array is not used.
 *
 *  DIRECT = 'F' and STOREV = 'C':         DIRECT = 'F' and STOREV = 'R':
 *
 *               V = (  1       )                 V = (  1 v1 v1 v1 v1 )
 *                   ( v1  1    )                     (     1 v2 v2 v2 )
 *                   ( v1 v2  1 )                     (        1 v3 v3 )
 *                   ( v1 v2 v3 )
 *                   ( v1 v2 v3 )
 *
 *  DIRECT = 'B' and STOREV = 'C':         DIRECT = 'B' and STOREV = 'R':
 *
 *               V = ( v1 v2 v3 )                 V = ( v1 v1  1       )
 *                   ( v1 v2 v3 )                     ( v2 v2 v2  1    )
 *                   (  1 v2 v3 )                     ( v3 v3 v3 v3  1 )
 *                   (     1 v3 )
 *                   (        1 )
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Dlarft()

dlarft(String, String, int, int, double[], int, int, double[], int, double[], int, int)

 public Dlarft()

 public static void dlarft(String direct,
                           String storev,
                           int n,
                           int k,
                           double v[],
                           int _v_offset,
                           int ldv,
                           double tau[],
                           int _tau_offset,
                           double t[],
                           int _t_offset,
                           int ldt)

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