1*DECK DJAC
2      SUBROUTINE DJAC (T, U, PD, NROWPD, RPAR, IPAR)
3C***BEGIN PROLOGUE  DJAC
4C***SUBSIDIARY
5C***PURPOSE  Evaluate Jacobian for DDEBDF quick check.
6C***LIBRARY   SLATEC
7C***TYPE      DOUBLE PRECISION (JAC-S, DJAC-D)
8C***AUTHOR  Chow, Jeff (LANL)
9C***ROUTINES CALLED  (NONE)
10C***REVISION HISTORY  (YYMMDD)
11C   810801  DATE WRITTEN
12C   891214  Prologue converted to Version 4.0 format.  (BAB)
13C   900415  Minor clean-up of prologue and code and name changed from
14C           DDJAC to DJAC.  (WRB)
15C***END PROLOGUE  DJAC
16      INTEGER IPAR, NROWPD
17      DOUBLE PRECISION PD, R, R5, RPAR, RSQ, T, U, U1SQ, U2SQ, U1U2
18      DIMENSION U(*), PD(NROWPD,*), RPAR(*), IPAR(*)
19C***FIRST EXECUTABLE STATEMENT  DJAC
20      U1SQ = U(1)*U(1)
21      U2SQ = U(2)*U(2)
22      U1U2 = U(1)*U(2)
23      RSQ = U1SQ + U2SQ
24      R = SQRT(RSQ)
25      R5 = RSQ*RSQ*R
26      PD(3,1) = (3.D0*U1SQ - RSQ)/R5
27      PD(4,1) = 3.D0*U1U2/R5
28      PD(3,2) = PD(4,1)
29      PD(4,2) = (3.D0*U2SQ - RSQ)/R5
30      PD(1,3) = 1.D0
31      PD(2,4) = 1.D0
32      RETURN
33      END
34