C DHPS 10
C ..................................................................DHPS 20
C DHPS 30
C SUBROUTINE DHEPS DHPS 40
C DHPS 50
C PURPOSE DHPS 60
C COMPUTES THE VALUE OF AN N-TERM EXPANSION IN HERMITE DHPS 70
C POLYNOMIALS WITH COEFFICIENT VECTOR C FOR ARGUMENT VALUE X. DHPS 80
C DHPS 90
C USAGE DHPS 100
C CALL DHEPS(Y,X,C,N) DHPS 110
C DHPS 120
C DESCRIPTION OF PARAMETERS DHPS 130
C Y - RESULT VALUE DHPS 140
C DOUBLE PRECISION VARIABLE DHPS 150
C X - ARGUMENT VALUE DHPS 160
C DOUBLE PRECISION VARIABLE DHPS 170
C C - COEFFICIENT VECTOR OF GIVEN EXPANSION DHPS 180
C COEFFICIENTS ARE ORDERED FROM LOW TO HIGH DHPS 190
C DOUBLE PRECISION VECTOR DHPS 200
C N - DIMENSION OF COEFFICIENT VECTOR C DHPS 210
C DHPS 220
C REMARKS DHPS 230
C OPERATION IS BYPASSED IN CASE N LESS THAN 1 DHPS 240
C DHPS 250
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED DHPS 260
C NONE DHPS 270
C DHPS 280
C METHOD DHPS 290
C DEFINITION DHPS 300
C Y=SUM(C(I)*H(I-1,X), SUMMED OVER I FROM 1 TO N). DHPS 310
C EVALUATION IS DONE BY MEANS OF UPWARD RECURSION DHPS 320
C USING THE RECURRENCE EQUATION FOR HERMITE POLYNOMIALS DHPS 330
C H(N+1,X)=2*(X*H(N,X)-N*H(N-1,X)). DHPS 340
C DHPS 350
C ..................................................................DHPS 360
C DHPS 370
SUBROUTINE DHEPS(Y,X,C,N) DHPS 380
C DHPS 390
DIMENSION C(1) DHPS 400
DOUBLE PRECISION C,Y,X,H0,H1,H2 DHPS 410
C DHPS 420
C TEST OF DIMENSION DHPS 430
IF(N)1,1,2 DHPS 440
1 RETURN DHPS 450
C DHPS 460
2 Y=C(1) DHPS 470
IF(N-2)1,3,3 DHPS 480
C DHPS 490
C INITIALIZATION DHPS 500
3 H0=1.D0 DHPS 510
H1=X+X DHPS 520
C DHPS 530
DO 4 I=2,N DHPS 540
H2=X*H1-DFLOAT(I-1)*H0 DHPS 550
H0=H1 DHPS 560
H1=H2+H2 DHPS 570
4 Y=Y+C(I)*H0 DHPS 580
RETURN DHPS 590
END DHPS 600