share/hompack/fortran/rhojs.f

   1       SUBROUTINE RHOJS(A,LAMBDA,X,QR,LENQR,PIVOT,PP,PAR,IPAR)
   2       INTEGER IPAR(1),LENQR,N,PIVOT(*)
   3       DOUBLE PRECISION A(*),LAMBDA,PAR(1),PP(*),QR(LENQR),X(*)
   4 C
   5 C PAR(1:*) AND IPAR(1:*) ARE ARRAYS FOR (OPTIONAL) USER PARAMETERS,
   6 C    WHICH ARE SIMPLY PASSED THROUGH TO THE USER WRITTEN SUBROUTINES
   7 C    RHOA, RHOJS.
   8 C
   9 C Evaluate the N X N symmetric Jacobian matrix [D RHO/DX] at (A,X,LAMBDA),
  10 C and return the result in packed skyline storage format in QR.  LENQR is
  11 C the length of QR, and PIVOT contains the indices of the diagonal elements
  12 C of [D RHO/DX] within QR.  PP contains -[D RHO/D LAMBDA] evaluated at
  13 C (A,X,LAMBDA).  Note the minus sign in the definition of PP.
  14 C
  15       RETURN
  16       END