C C .................................................................. C C SUBROUTINE DQHSE C C PURPOSE C TO COMPUTE THE VECTOR OF INTEGRAL VALUES FOR A GIVEN C EQUIDISTANT TABLE OF FUNCTION, FIRST DERIVATIVE, C AND SECOND DERIVATIVE VALUES. C C USAGE C CALL DQHSE (H,Y,FDY,SDY,Z,NDIM) C C DESCRIPTION OF PARAMETERS C H - DOUBLE PRECISION INCREMENT OF ARGUMENT VALUES. C Y - DOUBLE PRECISION INPUT VECTOR OF FUNCTION VALUES. C FDY - DOUBLE PRECISION INPUT VECTOR OF FIRST DERIVATIVE. C SDY - DOUBLE PRECISION INPUT VECTOR OF SECOND DERIVATIVE. C Z - RESULTING DOUBLE PRECISION VECTOR OF INTEGRAL C VALUES. Z MAY BE IDENTICAL WITH Y, FDY OR SDY. C NDIM - THE DIMENSION OF VECTORS Y,FDY,SDY,Z. C C REMARKS C NO ACTION IN CASE NDIM LESS THAN 1. C C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED C NONE C C METHOD C BEGINNING WITH Z(1)=0, EVALUATION OF VECTOR Z IS DONE BY C MEANS OF HERMITEAN SIXTH ORDER INTEGRATION FORMULA. C FOR REFERENCE, SEE C R.ZURMUEHL, PRAKTISCHE MATHEMATIK FUER INGENIEURE UND C PHYSIKER, SPRINGER, BERLIN/GOETTINGEN/HEIDELBERG, 1963, C PP.227-230. C C .................................................................. C SUBROUTINE DQHSE(H,Y,FDY,SDY,Z,NDIM) C C DIMENSION Y(1),FDY(1),SDY(1),Z(1) DOUBLE PRECISION Y,FDY,SDY,Z,H,HH,HF,HT,SUM1,SUM2 C SUM2=0.D0 IF(NDIM-1)4,3,1 1 HH=.5D0*H HF=.2D0*H HT=.08333333333333333D0*H C C INTEGRATION LOOP DO 2 I=2,NDIM SUM1=SUM2 SUM2=SUM2+HH*((Y(I-1)+Y(I))+HF*((FDY(I-1)-FDY(I))+ 1 HT*(SDY(I-1)+SDY(I)))) 2 Z(I-1)=SUM1 3 Z(NDIM)=SUM2 4 RETURN END