NF01BV

Computation of the matrix J' J + c I, for a full Jacobian J (one output variable)

Purpose

  To compute the matrix J'*J + c*I, for the Jacobian J as received
  from SLICOT Library routine NF01BY, for one output variable.

  NOTE: this routine must have the same arguments as SLICOT Library
  routine NF01BU.

      SUBROUTINE NF01BV( STOR, UPLO, N, IPAR, LIPAR, DPAR, LDPAR, J,
     $                   LDJ, JTJ, LDJTJ, DWORK, LDWORK, INFO )
C     .. Scalar Arguments ..
      CHARACTER         STOR, UPLO
      INTEGER           INFO, LDJ, LDJTJ, LDPAR, LDWORK, LIPAR, N
C     .. Array Arguments ..
      INTEGER           IPAR(*)
      DOUBLE PRECISION  DPAR(*), DWORK(*), J(LDJ,*), JTJ(*)

Mode Parameters

  STOR    CHARACTER*1
          Specifies the storage scheme for the symmetric
          matrix J'*J + c*I, as follows:
          = 'F' :  full storage is used;
          = 'P' :  packed storage is used.

  UPLO    CHARACTER*1
          Specifies which part of the matrix J'*J + c*I is stored,
          as follows:
          = 'U' :  the upper triagular part is stored;
          = 'L' :  the lower triagular part is stored.

  N       (input) INTEGER
          The number of columns of the Jacobian matrix J.  N >= 0.

  IPAR    (input) INTEGER array, dimension (LIPAR)
          The integer parameters describing the structure of the
          matrix J, as follows:
          IPAR(1) must contain the number of rows M of the Jacobian
                  matrix J.  M >= 0.
          IPAR is provided for compatibility with SLICOT Library
          routine MD03AD.

  LIPAR   (input) INTEGER
          The length of the array IPAR.  LIPAR >= 1.

  DPAR    (input) DOUBLE PRECISION array, dimension (LDPAR)
          The real parameters needed for solving the problem.
          The entry DPAR(1) must contain the real scalar c.

  LDPAR   (input) INTEGER
          The length of the array DPAR.  LDPAR >= 1.

  J       (input) DOUBLE PRECISION array, dimension (LDJ,N)
          The leading M-by-N part of this array must contain the
          Jacobian matrix J.

  LDJ     INTEGER
          The leading dimension of the array J.  LDJ >= MAX(1,M).

  JTJ     (output) DOUBLE PRECISION array,
                   dimension (LDJTJ,N),    if STOR = 'F',
                   dimension (N*(N+1)/2),  if STOR = 'P'.
          The leading N-by-N (if STOR = 'F'), or N*(N+1)/2 (if
          STOR = 'P') part of this array contains the upper or
          lower triangle of the matrix J'*J + c*I, depending on
          UPLO = 'U', or UPLO = 'L', respectively, stored either as
          a two-dimensional, or one-dimensional array, depending
          on STOR.

  LDJTJ   INTEGER
          The leading dimension of the array JTJ.
          LDJTJ >= MAX(1,N), if STOR = 'F'.
          LDJTJ >= 1,        if STOR = 'P'.

  DWORK   DOUBLE PRECISION array, dimension (LDWORK)
          Currently, this array is not used.

  LDWORK  INTEGER
          The length of the array DWORK.  LDWORK >= 0.

  INFO    INTEGER
          = 0:  successful exit;
          < 0:  if INFO = -i, the i-th argument had an illegal
                value.

  The matrix product is computed columnn-wise, exploiting the
  symmetry. BLAS 3 routine DSYRK is used if STOR = 'F', and BLAS 2
  routine DGEMV is used if STOR = 'P'.

  None

Program Text

  None

  None

  None