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